Glossary of botanical terms
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This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology. For other related terms, see Glossary of phytopathology, Glossary of lichen terms, and List of Latin and Greek words commonly used in systematic names.
A
In the bud,
Tetradenia riparia leaves have their upper surfaces turned toward the stem and the
axil. The lower surface is
abaxial ("away from the axis"), and the upper surface is
adaxial.
Viburnum abscission
Welwitschia mirabilis presents an example of an
acaulescent growth
habit unusual in so large a plant species.
Schematic diagrams of the
accumbent arrangement of the
cotyledons and
radicle in a seed of
Erysimum (formerly Cheiranthus)
Achenes on the surface of the stem of the
infructescence of a strawberry
Geranium incanum flowers are
actinomorphic, having five axes of symmetry, as opposed to the two axes of symmetry of the
zygomorphic flowers of most species of the related genus
Pelargonium.
Fern frond with
acuminate leaflets
Adelphous stamens in flower of
Gossypium tomentosum
Watsonia flower slit open and with one
stamen bent upward to show its
adnate attachment to the petal
Diagram of a coconut fruit. The
albumen (endosperm) is labelled Alb.
Caffeine is an
alkaloid with four nitrogen atoms in its carbon skeleton.
Rothmannia leaf with extensively
anastomose venation
Androgynous flower of
Sandersonia aurantiaca cut open longitudinally to show the
androecium, which comprises the
anthers surrounding the green central
pistil
Anther of
Lilium in a state of
anthesis,
dehiscent and releasing
pollen
A
Neea species, family
Nyctaginaceae, presents an example of an
anthocarp: the
calyx and
style remain around the ripening fruit.
Aphananthous flowers of oaks such as
Quercus robur, being
anemophilous, have no need of being conspicuous to pollinating animals.
Apical bud of a
Populus (poplar) shoot
The apparently separate nuts of
Ochrosia borbonica actually are
apocarpous carpels, two from each flower.
Apophyses on the tips of the cone scales of
Araucaria cunninghamii amount to spikes.
Hairs on the leaves of
Meniocus linifolius (formerly Alyssum linifolium) are
stellate and
appressed to the leaf surface.
Arachnoid leaves of an unidentified
Gazania species
Spines of cactus
Gymnocalycium bayrianum emerging from the
areoles of the stem
nodes
Seeds of a species of
Blighia (ackee), one whole and one in longitudinal section, showing the pale
aril
Infructescence of wild rye, showing prominent
awns
Anatomy of an
awn and bristles on a species of the Australian grass
Rytidosperma longifolium
Axillary buds in leaf
ab-
Prefix meaning "position away from".
abaxial
Surface of an organ facing away from the organ's axis, e.g. the lower surface of a lateral organ such as a leaf or petal.
Contrast
adaxial.
abort
To abandon development of a structure or organ.
abscission
Natural shedding of an organ that is mature or aged, as of a ripe fruit or an old leaf.
abscission zone
Specialized layer of tissue that allows an organ to be shed by
abscission when it is ripe or senescent. Such tissue is commonly formed, for example, at the base of a
petiole or
pedicel.
acaulescent
Having no apparent
stem, or at least none visible above the ground surface.
Examples include some species of
Oxalis,
Nolina,
and
Yucca.
Antonym:
caulescent (possessing stem).
accrescent
Increasing in size with age, such as a
calyx that continues to grow after the
corolla has fallen,
e.g. in
Physalis peruviana.
accumbent
Lying against another part of the plant; when applied to a
cotyledon, it means that an edge of the cotyledon lies along the folded
radicle in the seed.
-aceae
Suffix added to the word stem of a
generic name to form the name of a taxonomic
family;
for example,
Rosaceae is the rose family, of which the
type genus is
Rosa.
achene
Dry, one-seeded
indehiscent fruit in which the true fruit is not the so-called "berry", but the achenes, which are the so-called "seeds" on the
infructescence, e.g. in the genus
Fragaria.
acicular
Slender or needle-shaped.
See also
Leaf shape.
acropetal
Moving from roots to leaves, e.g. of molecular signals in plants.
acrophyll
Regular
leaves of a mature plant, produced above the base, as opposed to
bathyphyll.
acrostichoid
(describing a type of
sorus) Covering the entire
abaxial surface of a
frond, usually densely so, as in
Elaphoglossum and
Acrostichum.
actino-
Prefix that indicates a
radial pattern, form, or morphology.
actinodromous
(of
leaf venation)
Palmate or
radially arranged venation with three or more
primary veins arising at or near the base of the leaf and reaching the
margin in most species, but not all.
actinomorphic
Regular or
radially symmetrical;
may be bisected into similar halves in at least two planes. Applies e.g. to
steles and flowers in which the
perianth segments within each whorl are alike in size and shape. Compare
regular. Contrast
asymmetrical,
irregular, and
zygomorphic.
aculeate
Armed with
prickles,
e.g. the stem of a rose.
acumen
A long, tapering point, especially the apex of an acuminate leaf.
acuminate
Tapering gradually to a point, with concave sides approaching the point.
Contrast
acute and
mucronate. See also
Leaf shape.
acute
1. Sharply pointed, but not drawn out, with straight sides approaching the point.
Contrast
acuminate. See also
Leaf shape.
2. Converging at an angle of less than 90°. Contrast
obtuse.
ad-
Prefix meaning "near or toward"; also meaning "added to".
adaxial
Surface of an organ facing toward the organ's axis,
e.g. the upper surface of a lateral organ such as a leaf or petal. Contrast
abaxial.
adelphia
A bundle or structure of stamens forming one unit in an
adelphous flower; for example, the stamen tube around the pistil of
Hibiscus.
adelphous
Having organs, particularly
filaments such as
stamens, connected into one or more
adelphiae, whether in the form of bunches or tubes, such as is commonly seen in families such as
Malvaceae. Usage of the term is not consistent; some authors include closely bunched filaments, while others include only adelphiae in which filaments are connected minimally at their bases. See, for example, Sims: "...the filaments are so closely pressed that they have the appearance of being monadelphous...".
Compare derived terms such as
monadelphous, having stamens growing in a single bunch or tube, for example in
Hibiscus, and
diadelphous, growing in two bunches.
adherent
Slightly united to an organ of another kind,
usually to a part of another whorl, e.g. a
sepal connected to a
petal. Contrast
adnate.
adnate
Grown from or closely fused to an organ of a different kind,
especially along a
margin, e.g. a
stamen fused to a petal. Adnate
anthers have their halves attached to the filament through most of their length. Contrast
connate.
adventitious
Produced in an unpredictable or unusual position,
e.g. an adventitious
bud produced from a
stem rather than from the more typical
axil of a
leaf. Adventitious
roots may develop from
nodes of
prostrate stems of some plant species, or from the
hypocotyl rather than from the
radicle of a germinating
monocotyledon.
adventive
Introduced accidentally
(usually referring to a
weed).
aerial
Of the air; growing or borne above the surface of the ground or water.
aestivation
Arrangement of
sepals and
petals or their
lobes in an unexpanded flower
bud. Contrast
vernation.
aff. (affinis)
With affinity to others, akin to; often used for a provisionally recognized but unnamed taxon considered close to that name, perhaps a
hybrid or extreme variant.
aggregate fruit
Cluster of
fruits formed from the free
carpels of a single flower, e.g. a
blackberry. Compare
multiple fruit.
agochoric
Plants that are spread through accidental transport.
agricultural weed
See
weed.
agriophyte
Plant species that have invaded native vegetation and could survive there without human intervention. They are established there in natural habitats, remaining part of natural vegetation even after human influence has ceased, and are independent of humans in their continued existence.
agrophic
Comb-like series of veins forking from a single side of a primary or secondary vein.
agrostology
The scientific study of grasses, in the strictest sense only those species which are members of the family
Poaceae. Broader usages sometimes also include grass-like or
graminoid species from the families
Cyperaceae,
Juncaceae, and
Typhaceae.
alate
Having a
wing or wings.
albumen
Older name for the
endosperm of flowering plants. Except for being a
storage tissue for nutrients, it is not like the albumen (
egg white) of animal embryos.
albuminous
(of
seeds) Containing
endosperm.
-ales
Suffix added to the stem of a
generic name or descriptive name to form the name of a taxonomic
order.
alien
Any plant introduced to an area outside its natural range. Often used interchangeably or in combination with foreign,
exotic, non-
native, and non-
indigenous.
alkaloid
Any of a loosely defined class of organic compounds found in the tissues of many species of plants. Alkaloid molecules have one or more alkaline-reacting
nitrogen atoms in their carbon structures. Many alkaloids are commercially important as drugs or poisons, e.g.
caffeine,
morphine,
quinine, and
strychnine, each of which occurs naturally in certain plants.
allelopathy
The secretion by a plant of biochemicals which influence the growth and reproduction of nearby plants.
allopatric
Having geographically separate, non-overlapping ranges of distribution.
Contrast
sympatric.
alternate
1. (adj.) (of
leaves or
flowers) Borne singly at different levels along a
stem, including spiralled parts. Contrast
opposite.
2. (prep.) Occurring between something else, e.g.
stamens alternating with
petals.
alternipetalous
A configuration where parts of the flower, e.g.
stamens, alternate in position with the
petals.
ament
A
synonym of
catkin.
amphitropous
(of an
ovule) Bent so that both ends are near each other. Contrast
anatropous,
campylotropous, and
orthotropous.
amplexicaul
With the base dilated and clasping the stem, usually of leaves.
amylum star
a vegetative propagative body filled with
starch (amylum) and located around the lower nodes of certain
stoneworts.
anastomose
Branching and then rejoining, as with
leaf venation.
anastomosis
A connection or fusion of two or more
veins that are normally diverging or branching, thereby forming a network.
anatropous
(of an
ovule) Inverted so that the
micropyle faces the
placenta (this is the most common ovule orientation in flowering plants). Contrast
amphitropous,
campylotropous, and
orthotropous.
ancipital
Flat, with two edges (versus round).
androdioecious
Having
bisexual flowers and male flowers on separate individuals. Contrast
andromonoecious,
polygamodioecious,
polygamomonoecious, and
polygamous.
androecium
A collective name for the male reproductive parts of a
flower; the
stamens of a flower considered collectively. Contrast
gynoecium. Abbreviated A; e.g. A 3+3 indicates six stamens in two
whorls.
androgynophore
A stalk bearing both the
androecium and
gynoecium of a flower above the level of
insertion of the
perianth.
androgynous
Having male and female flowers in the same
inflorescence.
androphore
The stalk or column supporting the
stamens in certain flowers.
andromonoecious
Having
bisexual flowers and male flowers on the same individual plant. Contrast
androdioecious,
gynomonoecious,
polygamodioecious,
polygamomonoecious, and
polygamous.
anemophilous
Adapted to
pollination by
wind.
anemophily
Adaptation to
pollination by
wind.
angiosperm
A
flowering plant; a plant with developing seeds enclosed in an
ovary.
anisomery
The condition of having a floral
whorl with a different (usually smaller) number of parts from the other floral whorls.
anisotomic
Branching, with branches having unequal diameters, such as a trunk and its branch. Contrast
isotomic.
annual
A plant that completes its life cycle (i.e. germinates, reproduces, and dies) within a single year or growing season.
annulus
1. A ring-like structure; in the form of a ring.
Pappus bristles are sometimes attached to a ring called an annulus or disk at the top of the
achene beak. In some
pollen grains, the exine around the apertures is either thicker or thinner. In pores, this border is termed an annulus. Certain flowers have ring-like constrictions at the mouth of the flower, e.g. in
Huernia and
Aristolochia.
2. A ring of specialized cells on the
sporangium.
anterior
Positioned in front of, toward the
apex. Compare
distal.
anthemoid
In the
Compositae, a
style with a brush-like tuft of sweeping hairs at the tip of each style branch.
anther
The
pollen-bearing part of a
stamen.
antheridium
in bryophytes, a specialized gametophytic organ that produces the male
gametes.
antheridiophore
In liverworts of the order Marchantiales, a male
gametophore, a specialized, stalked structure that bears the
antheridia.
antherode
A sterile
anther of a
staminode.
anthesis
1. (of a flower) The period during which
pollen is presented and/or the
stigma is receptive.
2. (of a flowering plant) The period during which flowers in anthesis are present. Not defined for some cases, such as when pollen is released in the bud.
anthocarp
A type of
fruit in which some part of the
flower persists attached to the
pericarp, e.g. in
Nyctaginaceae.
anthophore
A stalk-like structure,
internode located between the
calyx and the other parts of the flower.
anticlinal
Pointing up, away from, or perpendicular to a surface. Contrast
periclinal.
antrorse
Directed forward or upward, e.g. of hairs on a stem. Contrast
retrorse.
apetalous
Lacking
petals.
apex
The tip; the point furthest from the point of attachment.
aphananthous
(of flowers) Inconspicuous or unshowy, as opposed to
phaneranthous or showy.
aphlebia
Imperfect or irregular leaf endings commonly found on ferns and fossils of ferns from the
Carboniferous Period.
aphyllous
Leafless; having no leaves.
apical
At or on the
apex of a structure, usually a
shoot, a
stem, or the
trunk of a tree, e.g. an apical
meristem or an apical
bud.
apiculate
especially of leaves, ending in a short triangular point. See also
Leaf shape.
apiphily
A form of
pollination whereby
pollen is distributed by
honey bees.
apo-
A prefix meaning "away from, separate, without".
apocarpous
(of a
gynoecium) Consisting of one or more
carpels which are free from one another (or almost so), e.g. in members of the
Ranunculaceae and
Dilleniaceae.
apomixis
A type of
asexual reproduction whereby viable
seeds or
spores are produced asexually, without
fertilization, such that the genetic material they contain is a clone of the parent's genetic material. A plant produced in this way is called an apomict.
apomorphy
In
cladistics, a "different form" from the form of an ancestor (i.e., an
innovation) of use in determining membership in a
clade.
apopetalous
Having separate
petals, not fused (
sympetalous).
apophyllous
Perianth or other segments free, not united. Compare
symphyllous,
gamophyllous, and
polyphyllous.
apophysis
1. The external part of a
cone scale.
2. An outgrowth of an organ or an enlargement of a
stem.
appendage
A secondary part attached to a main structure; an external growth that seldom has any obvious function, hence
appendiculate.
appendiculate
Having the nature of or bearing
appendages.
appressed
Pressed closely but not fused, e.g. leaves against a stem.
aquatic plant
A plant whose natural habitat is water, living in or on water for all or a substantial part of its lifespan; generally restricted to fresh or inland waters.
arachnoid
Cobwebby, from being covered with fine white hairs.
arborescent
Tree-like in growth or general appearance.
arboretum
A taxonomically arranged collection of
trees.
archaeophyte
A non-
native plant that has nonetheless been present in a particular geographic area for some time. Contrast
neophyte.
archegonium
A multicellular haploid structure or organ of the
gametophyte phase of certain plants, producing and containing the ovum or female gamete. The corresponding male organ is called the
antheridium.
archegoniophore
In liverworts of the order Marchantiales, a female
gametophore: a specialized, stalked structure that bears the
archegonia and the
sporophytes.
arctotoid
In the
Compositae, a
style with a ring of sweeping hairs borne on the shaft of the style proximal to the style branches.
areolate
Having or being composed of
areoles, as an areolate
crustose lichen.
areole
1. A space between the threads of a net, e.g. that part of a
leaf surface defined by each of the elements of a
vein network; as with cacti, the area between the veinlets of a leaf.
2. A structure on the stem
node of a
cactus,
morphologically a specialised branch; the region of a cactus upon which
spines,
glochids, and flowers are borne.
aril
A membranous or fleshy
appendage formed by expansion of the
funicle which partly or wholly covers a
seed, e.g. the fleshy outer layer of
lychee fruit, or that found in members of the
Sapindaceae.
aristate
With a stiff, bristle-like
awn or tip. See also
Leaf shape.
article
A segment of a jointed
stem or of a
fruit with constrictions between the seeds; an organ part that separates easily from the rest of the organ at a joint or articulation.
articulate
Jointed; separating freely, leaving a clean scar; e.g. the
fronds of certain ferns where they join the
rhizome.
ascending
1. (of a
stem) Spreading horizontally, then directed upward; an ascending stem is more or less
prostrate near its base, then
erect.
2. (of an
ovule) Attached somewhat above the base.
ascidiate
Shaped like a pitcher, as with the leaves of pitcher plants, e.g. species of
Nepenthes and
Sarracenia.
asexual reproduction
Reproduction that does not involve
gametes. Often used interchangeably with
vegetative reproduction.
asperulous
Having a rough, sandpapery texture; e.g. some leaf surfaces.
asymmetrical
Irregular or unequal; lacking any
plane of symmetry; e.g. flowers of
Canna.
attenuate
Narrowing gradually. See also
Leaf shape.
auricle
An ear-shaped
lobe, particularly a small, roundish, lateral
appendage of a
leaf or leaf-like organ.
auriculate
Attached at the base with ear-shaped appendages (
auricles). See also
Leaf shape.
autogamous
Self-pollinating, self-fertilizing – in flowering plants
awn
1. Any long, bristle-like
appendage.
2. In the
Poaceae, an appendage terminating or on the back of
glumes or
lemmas of some grass
spikelets.
3. In the
Geraniaceae, the part of the
style that remains attached to the
carpel that separates from the
carpophore (column).
4. A generally straight, stiff
pappus element, varying from stiffly bristle-like to hard and needle-like. In
Strophanthus, the awn is the beak of the
seed,
stipe of the
coma hairs.
axil
The upper angle between one part of a plant and another, e.g. the stem and a leaf.
axile
On an axis; of a
placenta, on the central axis of the
ovary.
axillary
Borne in or arising from the
axil, usually referring to the axil of a leaf.
axis
The main
stem of a whole plant or
inflorescence; also, the line along which this stem extends.
B
Baculiform desmid in genus
Closterium
Barbs occur on the spines of some species of cactus, as shown here, enlarged.
Berries of
Olinia ventosa, including a cross-section showing hard seeds in the pulp
The
bifoliate compound leaves of the mopane tree,
Colophospermum mopane, suggest the common name "butterfly tree".
Cross-section of a
silique of
Arabidopsis thaliana, showing it to be
biloculate, formed of two
carpels, morphologically a silique and not a
pod
Bipinnate leaf of
Gymnocladus dioicus
Structure of a
biternate compound leaf
This African baobab,
Adansonia digitata, has an enormous
bole beneath a relatively modest
canopy that is typical of this species.
The large, colorful
bracts of
Bougainvillea are commonly mistaken for its petals.
Burrs, fruits of
Arctium species
Buttress root of a mature
elm
baccate
Fruit appearing like a berry that may or may not be a true berry.
baculiform
Rod-like; longer than wide. Compare
cylindrical.
barb
A rear-facing point, as in a
fish hook.
barbed
Having
barbs pointing in one direction.
barbellate
Having
barbed hairs (barbellae).
bark
The protective external layer of tissue on the
stems and
roots of
woody trees and shrubs; includes all of the living and non-living tissue external to the
cambium.
basal
Situated or attached at or close to the base (of a plant or a
phylogenetic tree diagram).
basifixed
Something attached by its base, e.g. an
anther attached to the
filament. Compare
dorsifixed.
basipetal
Developing sequentially from the
apex toward the base (i.e. with the youngest toward the base), e.g. of flowers in an
inflorescence. Also, moving from leaves to roots, e.g. of molecular signals in plants.
bathyphyll
A specialized
leaf produced at the base of a plant, usually when the plant is immature, and which serves to anchor the plant to a substrate; especially notable in the fern
Teratophyllum. Contrast
acrophyll.
beak
A prominent, pointed terminal projection, especially of a
carpel or
fruit.
berry
A type of
indehiscent fruit with the
seeds immersed in the pulp, e.g. a
tomato.
bi-
A prefix meaning "two", e.g.
bisulcate, having two sulci or grooves.
biennial
A plant which completes its life cycle (i.e. germinates, reproduces, and dies) within two years or growing seasons. Biennial plants usually form a basal
rosette of leaves in the first year and then flower and fruit in the second year.
bifid
Forked; cut in two for about half its length. Compare
trifid.
bifoliate
(of a
compound leaf) Having precisely two
leaflets, usually in a symmetrical pair, e.g. a leaf of
Colophospermum mopane. Compare
jugate lobed leaf, e.g. most species of
Bauhinia.
bifusiform
Fusiform with a pinch in the middle.
bilabiate
Having two lips, e.g. the form of the
petals in many
irregular flowers.
bilateral
1. Having two distinguishable sides, such as the two faces of a
dorsiventral leaf.
2. Arranged on opposite sides, e.g.
leaves on a
stem; Compare
distichous and
opposite.
3. Bilaterally symmetrical, as in a leaf with a symmetrical outline.
biloculate
Having two
loculi, e.g. in
anthers or
ovaries.
binomial
Making use of names consisting of two words to form the scientific name (or combination) in a Latin form. For example, where the first is the name of the
genus to which the
species belongs, and the second is the
specific epithet given to that species to distinguish it from others in the same genus.
binomial nomenclature
The system of nomenclature in which the scientific name of a
species (and not of a taxon at any other rank) is a combination of two names, the first name being the
generic name. The second name is referred to botanically as the
specific epithet. Note that the two names together (not just the second name) constitute the species name.
bipinnate
Doubly
pinnate; e.g. a
compound leaf with individual
leaflets pinnately divided.
bipinnatisect
A
pinnatisect leaf with deeply dissected segments.
bisexual
Bearing both male and female reproductive organs; usually, flowers with both
stamens and
carpels;
synonymous with
hermaphrodite,
synoecious, and
monoclinous. Bisexual flowers occur only on
monoecious plants. See also
androgynous,
monoicous, and
plant reproductive morphology.
bitegmic
(of an
ovule) Covered by two
integuments. Contrast
unitegmic.
biternate
Ternate, with each division divided into three.
bivalve
Having two
valves or hinged parts. Contrast
trivalve.
blade
The
lamina or flattened part of a
leaf, excluding the stalk or
petiole.
bloom
A fine white or bluish waxy powder occurring on plant parts, usually stems, leaves, and fruits. It is easily removed by rubbing.
bole
The
trunk of a tree, usually the portion below the lowest branch. Compare
canopy.
bostrychoid
Arranged on a conical surface (like a snail shell); used to describe
inflorescences in which the
buds are arranged in an almost helical manner on the outside of a long, tapering, conical
rachis.
bract
A modified
leaf associated with a
flower or
inflorescence and differing in shape, size, or color from other leaves (and without an
axillary bud).
bracteate
Possessing
bracts.
bracteole
A small
bract borne singly or in pairs on the
pedicel or
calyx;
synonymous with
bractlet.
bracteolate
Possessing
bracteoles (bractlets).
bracteose
Having many or showy
bracts.
bractlet
See
bracteole.
branchlet
A small
branch.
brevideciduous
A plant that loses all of its leaves only briefly before growing new ones, so that it is leafless for only a short time, e.g. approximately two weeks.
bristle
A straight, stiff hair (smooth or with minute teeth); the upper part of an
awn (when the latter is bent and has a lower, stouter, and usually twisted part, called the
column).
brochidodromous
Pinnate leaf venation in which the
secondary veins do not terminate at the leaf
margin, but are
joined in a succession of prominent
arcs.
brochus
Width of one lumen of a
pollen grain reticulum and half of the width of the surrounding muri (walls), hence heterobrochate and homobrochate, where the lumina are of different or similar sizes, respectively.
bryophyte
Informally, any plant that is a
moss,
hornwort, or
liverwort. Formally, these plants are placed in three separate divisions: hornworts (
Anthocerophyta), liverworts (
Marchantiophyta), and mosses (
Bryophyta).
bulb
A thick storage organ, usually underground, consisting of a stem and leaf bases (the inner ones fleshy).
bulbel
A
bulb arising from another bulb. See
bulblet.
bulbil
A small, deciduous
bulb or
tuber formed in the
axil of a leaf or
pinna; a means of vegetative propagation.
bulblet
A
bulb arising from another bulb; a
bulbel.
bullate
1. Having a rounded or blister-like appearance; arched or vaulted.
2. (of a leaf) Having arched leaf tissue between each lateral vein, i.e. the veins appear depressed in the leaf surface.
burl
A deformation or knot in the branches or trunk of a tree, sometimes sought after in woodworking.
burr
1. A prickly
fruit.
2. A rough or prickly propagule consisting of a
seed or fruit and associated floral parts or
bracts.
buttress root
A
root growing from an above-ground stem or trunk, and providing support, e.g. commonly of
Ficus macrophylla.
C
Dianthus chinensis has a
caespitose growth habit.
Callus tissue of
Nicotiana tabacum growing on a nutrient medium in
plant tissue culture
Structure of flower of an orchid in genus
Praecoxanthus, with the
callus labelled
Bearded
callus of a floret of the grass species
Chrysopogon filipes
Scanning electron micrograph of the
carpopodium at the base of the achene-like fruit of
Zyzyura mayana, Asteraceae
Dormant leaf buds of deciduous trees are commonly protected by imbricate
cataphylls that are shed when the bud sprouts.
Male
catkins of
Betula pendula
The
caudex of
Dioscorea elephantipes grows largely above the soil surface. Many species that form caudices grow them underground.
Flowers growing from a branch of
Syzygium moorei, an example of
cauliflory
Some members of the
Espeletia genus exhibit a growth habit that is
caulirosulate.
Moehringia growing as a
chasmophyte on an overhanging cliff
Chloroplasts within the cells of the leaves of the moss
Bryum capillare
Not all
chloroplasts are simple in shape. Chloroplasts of
Spirogyra are helical within the tubular cells of their algal filaments.
Circinate vernation of
crosiers of the fern
Sadleria cyatheoides
The so-called "fleshy leaves" of cacti, such as on this
Opuntia tomentosa, are actually
cladodes (branches). The true leaves are the
spines growing on the cladodes, which on this young cladode are still fleshy.
Colony of cells forming a
coenobium, of an
alga in the genus
Pediastrum
Asclepias syriaca seeds, showing the
coma of hairs in its
pappus
Curcuma pseudomontana with red
coma bracts
Pfaffia gnaphalioides flowers with basal
coma hairs
Coma atop
Muscari armeniacum, bearing sterile flowers
The conical
compound inflorescence of
Aeonium arboreum is a compound
panicle composed of minor panicles, some of which are compound in their turn.
California buckeye (
Aesculus californica) has a
compound palmate leaf, the leaflets radiating from a central point.
The lobes of the
gamopetalous corolla of
Nicotiana flowers are
conduplicate in the bud.
Casuarina equisetifolia male and female flowers and
cones
Gamopetalous Watsonia flower split open between two petals to show the
connate formation of the
corolla tube; compare the
adnate attachment of the stamen bases to the matching petals
Corms, one entire in its
tunic, one partly peeled to show tunic
cataphylls, and one split to show inner structure
The
corona of this
Passiflora flower is a ring of purple
filaments between the
petals and the
stamens.
Cotyledons of seedlings of
Koelreuteria. One plant shows the first new leaves above its cotyledons, and the rest show various younger stages of emerging cotyledons.
Crassula rupestris frequently grows as a
cremnophyte on cliff faces in
fynbos.
Nymphoides crenata has
crenate leaf margins.
Mimetes cucullatus, so named for the hooded,
cucullate shape of its white flowers
Murraya paniculata has leaves with
cuneate (wedge-shaped) bases.
Examples of
cupules of
Fagaceae:
A:
Quercus rubra B:
Quercus trojanaC:
Fagus sylvatica D:
Castanea sativa
Cuspidate leaves of
Diplacus bigelovii var. cuspidatus
Euphorbia milii is commercially grown for the aesthetic appearance of its brightly colored,
bract-like structures called
cyathophylls, which sit below the
inflorescence.
caducous
Falling off early, e.g. the
sepals of poppies, which fall off when the
petals begin to open. Compare
persistent and
fugacious.
caespitose
Tufted or turf-like, e.g. the growth form of some grasses.
calcarate
possessing a
spur.
calcareous
A
soil type or a lichen substrate rock type that is rich in or largely composed of
calcium carbonate.
calceolate
Shaped like a slipper.
calcicole
A plant which thrives in
calcareous soil. Also calciphile, calciphyte.
Antonym: calcifuge.
callose
Hardened; thickened; callous.
callus
1. A protruding mass of tissue
2. Undifferentiated tissue growth formed in response to wounding; may be grown in vitro.
3. In orchids, fleshy outgrowths from the
labellum which can be variously shaped from
papillae to plates.
4. In grasses, a hardened extension from the base of a
floret (formed from the
rachilla joint and/or the base of the
lemma), which may or may not elongate and is often covered in hairs or bristles.
calyciflorous
Having
petals and
stamens attached to the
calyx.
calycophyll
Leaf-like structure formed from a
sepal or
calyx lobe which enlarges, usually many-fold, before or after
anthesis, especially when most of the other sepals or calyx lobes retain their original size. More extreme than an
accrescent calyx, calycophylls are found in
Rubiaceae. Compare
semaphyll and
pterophyll.
calyculate
Having an
epicalyx.
calyculus
1. A cup-shaped structure formed from
bracts resembling an outer
calyx.
2. In some
Asteraceae, a circle of bracts below the
involucre.
calyptra
A hood or lid. See
operculum.
calyx
Collective term for the
sepals of one flower; the outer
whorl of a flower, usually green. Compare
corolla.
calyx tube
A tube formed by the fusion of the sepals (
calyx), at least at the base.
cambium
Tissue layer that provides partially undifferentiated cells for plant growth.
campanulate
Bell-shaped.
camptodromous
Pinnate venation in which the
secondary veins curve toward the margins, in some cases becoming nearly parallel with them, and not reconnecting with other veins to form loops.
campylotropous
When the
ovule is oriented transversely (i.e. with its axis at right angles to its stalk) and with a curved
embryo sac. Compare
amphitropus,
anatropous, and
orthotropous.
canaliculate
Channelled; having a longitudinal groove.
canescent
Approaching white in color, as in a leaf covered with white down or wool.
canopy
Branches and foliage of a tree; the
crown. Also refers to the protective upper layer of a forest. Compare
trunk.
capillary
1. Tube, pore, or passage with a narrow, internal cross-section.
2. Slender; hair-like.
capitate
1. (of an
inflorescence) Having a knob-like head, with the flowers unstalked and aggregated into a dense cluster.
2. (of a
stigma) Like the head of a pin.
capitulum
Dense cluster of
sessile or
subsessile flowers or
florets, e.g. a flower
head in the daisy family
Asteraceae. See
pseudanthium.
capsule
Dry
fruit formed from two or more united
carpels and
dehiscing when ripe (usually by splitting into pieces or opening at summit by teeth or pores).
carduoid
In
Asteraceae, having a
style with a ring of sweeping hairs borne on the shaft of the style below the style branches.
carina
See
keel.
carinal canal
Longitudinal cavity in the
stems of
Equisetum and extinct
Equisetopsida, coinciding with a ridge in the stem surface.
carneous
Flesh-colored, especially as applied to some flowers.
carnose, carnous
Fleshy or pulpy in texture, especially as applied to some tissues or organs. Contrast
coriaceous and
corneous.
Caropodium
Genus of flowering plants in the family
Apiaceae. Native range: Turkey to Iran. Not to be confused with
Carpopodium
carpel
The basic female reproductive organ in
angiosperms, either consisting of a single
sporophyll or a single
locule of a compound
ovary, with a
style and a
stigma. The
gynoecium is the collective term for all of the carpels of a single
flower.
carpellary
Referring to carpels or to associated structures or outgrowths of carpels, for example
staminodes attached to carpels in Nymphaeaceae, were frequently referred to as carpellary attachments. The current and past usage of the terms "carpellary attachments",
paracarpels, and
staminodes is confused and varies among authors.
carpopodium
On
achenes (Cypselae), an elongation of the base of the
gynoecium which looks distinct; the
abscission zone, where the achene is separated from the
receptacle.
2. Genus
Carpopodium in the family
Brassicaceae; not to be confused with
Caropodium.
cartilaginous
Hard and tough; gristly. Compare
corneous and
coriaceous.
caruncle
A small piece of flesh-like tissue, typically lumpy or warty, growing on the
testa near the
hilum. Contrast
aril.
caryopsis
A dry,
indehiscent, one-seeded
fruit in which the
seed coat is closely fused to the fruit wall, e.g. in most grasses.
Casparian strip
A continuous band of
suberin in the radial primary cell walls of the
endodermis in vascular plant stems and roots that forms a permeability barrier to the passive diffusion of external water and solutes into the vascular tissue.
cassideous
Hood-, helmet- or bonnet-shaped; generally referring to floral anatomy, e.g. in the flowers of
Aconitum,
Satyrium, etc.
castaneous
Chestnut-colored, reddish-brown.
casual alien
An exotic plant that appears with no apparent human assistance but does not develop a sustained population(s), or one that persists only by repeated new introductions. Compare
alien.
cataphyll
Any plant structure which is morphologically a
leaf but which has at most an incidental or transient
photosynthetic function. They are either shed when their main function has been completed, or are incorporated into structures where, when dead, they serve a protective or supportive purpose.
catenulate
In the shape of a chain; formed of parts or cells connected as if chained together, e.g. some
diatoms,
algae, and
cyanobacteria such as
Anabaena. See also
concatenate.
catkin
A
spike, usually pendulous, in which the mostly small
flowers are
unisexual and without a conspicuous
perianth, e.g. in
willows,
poplars,
oaks, and
casuarinas. The individual flowers often have scaly
bracts and are generally
wind-pollinated. Catkins are usually shed as a unit.
caudate
Having a narrow, tail-like appendage or tip, e.g. a
drip tip. Contrast
acuminate,
cuspidate, and
mucronate.
caudex
The
stem of a plant, especially a
woody one; also used to mean a
rootstock, or particularly a
basal stem structure or storage organ from which new growth arises. Compare
lignotuber.
caudiciform
Stem-like or
caudex-like; sometimes used to mean "
pachycaul", meaning "thick-stemmed".
caulescent
possessing a well-developed
stem above ground, similar to
cauline.
Antonym:
acaulescent (lacking an apparent stem).
cauliflory
Having flowers or fruits growing directly from a tree's branches or trunk.
cauline
Borne on an aerial
stem or
caulis, as with leaves, flowers, or fruits (when applied to the latter two organs, usually referring to older stems.
caulirosulate
Borne at the end of the
stem or
caulis, as with leaves or bracts.
cell
1. The basic, microscopic unit of plant structure, generally consisting of compartments in a viscous fluid surrounded by a
cell wall.
2. A cavity of an
anther or
ovary.
cenanthous
(of a
perianth) Lacking both
stamens and
pistil, i.e. a flower with neither
androecium nor
gynoecium.
centrifixed
Of a two-branched organ attached by its center, e.g. a hair or
anther.
ceraceous
Having a waxy appearance, color, or texture, e.g. flowers of many species of
Ceropegia, and the waxy fruit of some species of
Myrica.
cernuous
Nodding, falling headlong or face down; inclined, stooping, or bowing forward. Applied to many species with a nodding, stooping
habit, such as many
Narcissus and
Dierama species. Many plant species bear the
specific epithet "cernua".
cespitose
An alternative spelling of
caespitose, meaning tufted or turf-like, e.g. the growth form of some grasses.
chamber
A cavity of an
ovary.
channelled
Sunken below the surface, resulting in a rounded channel.
chartaceous
Having a papery texture.
chasmogamous
Of flowers that are pollinated when the
perianth is open. Compare
cleistogamous.
chasmophyte
A plant adapted to growing in crevices or hollows, such as in cliff faces. Compare
cremnophyte.
chimera
An individual composed of two or more genetically distinct tissues, most commonly as a result of a
graft and sometimes by mutations that occur during cell division or cellular transfers during seed development.
chiropterophilous
Pollinated by
bats.
chlorophyll
Any of a variety of different chemical pigments in
chloroplasts that are essential for
photosynthesis.
chloroplast
An
organelle present in plant cells which contains
chlorophyll.
chlorosis
An abnormal lack or paleness of color in a normally green organ.
cilia
Very small hairs or hair-like protrusions more or less confined to the
margins of an organ, as with eyelashes; in motile cells, minute, hair-like protrusions which aid
motility.
circinate
Spirally coiled with the tip innermost, e.g. circinate
vernation of the developing
fronds of most ferns.
cirrhose
(of a leaf) Ending in a
tendril at the
apex.
cirrus
See
tendril.
cladode
A
photosynthetic branch or
stem, often leaf-like and usually with foliage leaves either absent or much reduced. Compare
phyllode.
class
The principal category for taxa ranking between
division and
order.
clathrate
Shaped like a net or lattice; pierced with apertures, as with a cage.
clavate
Club-shaped.
clavuncula
In the
Apocynaceae, an enlarged, drum-shaped
stigma of which the sides and lower surface are the receptive zones. Coherent with the
anthers or not.
claw
1. A narrow, stalk-like,
basal portion of a
petal,
sepal, or
bract.
2. In
Melaleuca, the united portion of a
stamen bundle.
cleistogamous
Having flowers which self-pollinate and never open fully, or which self-pollinate before opening. Compare
chasmogamous.
climber
A plant growing more or less
erect by leaning on or twining around another structure for support, or by clinging with
tendrils.
climbing
See
climber.
cline
A continuous morphological variation in form within a species or sometimes between two species.
clone
A plant derived from the asexual vegetative reproduction of a parent plant, with both plants having identical genetic compositions.
coalescent
Having plant parts fused or grown together to form a single unit.
cochleariform
Concave and spoon-shaped.
cochleate
Coiled like a snail's shell.
coenobium
An arranged colony of
algae that acts like a single organism.
coenocyte
A single cell with multiple
nuclei, formed when nuclear division was not followed by
cytokinesis.
coleoptile
One type of
sheath in the structure of
monocotyledonous seeds. The coleoptile is a protective sheath or cap (
pileus), generally more or less pointed, that covers the monocotyledonous
plumule as it emerges from the soil. It generally turns green and contributes to photosynthesis until its function is superseded by the main growth of the seedling. Contrast this with the
coleorhiza, which remains underground until it is superseded as the roots emerge.
coleorhiza
One type of
sheath in the structure of
monocotyledonous seeds. The coleorhiza connects the coleoptile to the
radicle and protects the monocotyledonous radicle during germination. Unlike the coleoptile, the coleorhiza is associated with the root and does not emerge from the soil during germination. Contrast
coleoptile.
collenchyma
A specialized tissue consisting of living cells with unevenly thickened
cellulose and
pectin cell walls that performs a support function in organs such as leaves and young stems that are composed of primary plant tissues.
colleter
A multicellular,
glandular hair that usually produces a mucilaginous substance and is located on
sepals,
stipules, or
petioles, or on nearby parts of
stems; commonly found on plants in the order
Gentianales.
columella
In flowering plants, the central axis of the
cone or
fruit, e.g. in
Callitris.
column
1. A structure extending above the
ovary and incorporating the
style and
stamens also known as the
gynostegium, e.g. in
orchids and
milkweeds.
2. In grasses, the lower, stouter, and usually twisted part of an
awn, distinct from the slender upper part or bristle.
columnar
Shaped like a column.
coma
1. A tuft of hairs from
testa or
funiculus at one or both ends of some seeds, e.g. in
Strophanthus,
Asclepias, or
Alstonia.
2. Sterile
bracts, e.g. in
Curcuma,
Ananas, or
Eucomis.
3. Sterile
flowers, e.g. in
Muscari and
Leopoldia, at the
apex of some
inflorescences.
4. A tuft of hairs at the base of some flowers, e.g. in
Pfaffia gnaphalioides.
5. A tuft of hairs at the apex or base of some
spikelets.
6. An
axil tuft of hairs in inflorescences in some
Poaceae, e.g. in
Eragrostis comata.
commercial name
A name often of no botanical standing and not governed by the
ICNCP. The term generally applies to names such as Trademark Names, names covered by Plant Breeders Rights, Patents and Promotional Names, which are often used to enhance the sale of a plant.
commissure
The seam or face at which two
carpels adhere. See also
fissure and
suture.
community
An ecological assemblage of plants that characteristically occur together.
compound
Composed of several parts, e.g. a
leaf composed of multiple
leaflets, a
gynoecium composed of multiple
carpels, or an
inflorescence made up of multiple smaller inflorescences.
compound palmate
Having
leaflets that radiate from a central point (usually at the top of a
petiole), like spread-out fingers radiating from the palm of a hand. Compare
palmate.
compressed
Flattened lengthwise, either laterally (from side to side) or dorsally (from front to back).
concatenate
Joined together in a chain-like form. See also
concatenate and
catenate.
concolorous
Having the same color throughout; uniformly colored.
conduplicate
Arranged such that two sides of a flat surface are folded along the midline to face each other. See also
ptyxis,
aestivation, and
vernation.
cone
A type of
fruit, usually
woody,
ovoid to
globular, including
scales,
bracts, or
bracteoles arranged around a central axis, e.g. in
gymnosperms, especially
conifers and
Casuarina.
conflorescence
A rarely used term describing substantial differences between the overall structure of an
inflorescence and that of its individual branches, e.g. the bottlebrush multiple-flower head of members of the genus
Callistemon.
connate
Fused to another organ (or organs) of the same kind, e.g.
petals in a
gamopetalous corolla tube. Compare
adnate.
connective
The part of an
anther that connects the anther cells.
connivent
Coming into contact or converging.
conspecific
Belonging to the same
species.
contiguous
Adjoining, touching, but not united.
contort
(of
sepals or
petals) A type of imbricate
aestivation in which one side of each segment overlaps one of the adjacent segments and the other side is overlapped by the other adjacent segment. See
convolute.
contorted
Twisted out of the normal shape.
convolute
1. Referring to the arrangement of floral or foliar organs in a
bud when each organ or segment has one edge overlapping the adjacent organ or segment; a form of
imbricate arrangement. See
contort.
2. (of
leaves) A type of
vernation in which one leaf is rolled up inside another.
3. A type of vernation of two leaves at a
node, in which one half of each leaf is exposed and the other half is wrapped inside the other leaf.
corcle
A plant
embryo,
plumule, or plumule plus
radicle.
cordate
Heart-shaped, with the notch lowermost; of the base of a
leaf, like the notched part of a heart. Contrast
obcordate.
coriaceous
Leathery; stiff and tough, but flexible. Compare
corneous.
corm
A fleshy, swollen
stem base, usually underground and functioning in the storage of food reserves, with
buds naked or covered by very thin scales; a type of
rootstock.
cormel
A small
corm (or cormlet), forming at the base of a growing larger corm.
corneous
Horny in texture; stiff and hard, but somewhat tough. Compare
coriaceous.
corolla
A collective term for the
petals of a
flower. Compare
calyx.
corona
1. In flowering plants, a ring of structures that may be united in a tube, arising from the
corolla or
perianth of a flower and standing between the perianth lobes and the
stamens. The trumpet of a
daffodil is a corona.
2. In grasses, a hardened ring of tissue surmounting the
lemma in some species.
cortex
A region of tissue located between the
surface cells and the
vascular cylinder.
corticolous
Growing on
bark or on wood with the bark stripped off. Compare
lignicolous.
corymb
An
inflorescence with branches arising at different points but reaching about the same height, giving the flower cluster a flat-topped appearance.
costa
A
rib.
costapalmate
Having a definite
costa (midrib), unlike the typical
palmate or fan leaf, but with the
leaflets arranged radially as in a palmate leaf.
cotyledon
The primary leaf or leaves of a plant embryo which upon germination develops into the seed-leaf or the first set of leaves.
craspedodromous
Pinnate venation in which the
secondary veins terminate at the
margins, often as teeth.
crateriform
In the shape of a saucer or shallow cup; hemispherical or more shallow.
cremnophyte
A plant adapted to growing on, especially hanging from, cliff faces or crevices. Compare
chasmophyte.
crenate
Having blunt or rounded teeth;
scalloped.
crenulate
Minutely scalloped.
crisped
Finely curled, as with the edges of leaves and petals.
cristarque cell
A
sclereid which contains a
druse and has the
lignin deposited excentrically on the
cell wall to form a cup shape, or in
cross-section, a ∪-shape.
crown
See
canopy.
cross
To make something interbreed; the act of hybridization.
cruciform
Cross-shaped.
crustaceous
Hard, thin and brittle.
crustose
Forming a closely applied surface layer or crust.
cryptogam
Any of the "lower plants" which produce
spores and do not have
stamens,
ovaries, or
seeds; literally, plants whose sexual reproductive organs are not conspicuous. This group typically includes the
ferns,
bryophytes, and
algae, and sometimes
fungi (including lichenized fungi). Compare
phanerogam.
cucullate
Hood-like or hooded, commonly referring to the shape of leaves or petals, e.g.
Pelargonium cucullatum. Similarly derived terms include cuculliform and cuccularis.
culm
In grasses, sedges, rushes, and some other
monocotyledons, an
aerial stem bearing the
inflorescence, extending strictly from the base of the plant to the lowest
involucral bract (or base of the inflorescence).
cultigen
A plant whose origin or selection is primarily due to intentional human activity.
cultivar
A term derived from "cultivated variety" denoting an assemblage of
cultivated plants clearly distinguished by one or more characters (morphological, physiological, cytological, chemical, or other). When reproduced (either sexually or asexually), the assemblage retains its distinguishing characters. A cultivar may arise in cultivation or be introduced from the wild. It is a variant that is of
horticultural interest or value. Cultivar names are written with single quotation marks around them, e.g. 'Blue Carpet' or 'Alba'. All new names established after 1 January 1959 must be in common language (that is, not in Latin), but names established in Latin prior to this date are retained in Latin form.
cultivar epithet
The defining part of a name that denominates a
cultivar. Cultivars are designated by fancy (q.v.) epithets appended either to the scientific name or to the common name of the taxon to which they belong; they are not italicized but placed in single quotation marks, e.g. Rubus nitidoides 'Merton Early'. 'Merton Early' is the cultivar epithet.
cuneate
Wedge-shaped, with straight sides converging at a base.
cupule
A cup-shaped structure composed of
coalescent bracts, such as the cup of an
acorn. See
calybium.
cupular
Shaped like a
cupule.
cupulate
Bearing
cupules.
cupuliform
Nearly hemispherical, shaped like a cupola or dome.
cusp
A hard, pointed tip, stiffer and more formidable than a
mucro, hence
cuspidate.
cuspidate
Tipped with a
cusp, as with some leaves.
cuticle
A waterproofing layer covering the
epidermis of
aerial plant surfaces and composed of the polymers
cutin, and/or
cutan and waxes.
cutting
An
apical tip of
shoot structure,
root, or
leaf which is cut from a plant and used for asexual vegetative propagation.
cyathium
An
inflorescence of
unisexual flowers surrounded by
involucral bracts, especially the flowers of
Euphorbia.
cyathophyll
In
Euphorbia, the
bract-like structure on which the
involucre sits, usually but not always occurring in twos. They may sometimes be brightly colored and confused with
petals.
cylindrical
Rod-like and two to three times as long as wide. Compare
baculiform.
cynaroid
See
carduoid.
cyme
A type of
inflorescence in which the main axis and all lateral branches end in a
flower (each lateral may be repeatedly branched).
cymose
Having a
cyme or cymes.
cypsela
A type of dry, one-seeded,
indehiscent fruit formed from an
inferior ovary.
D
Seasonal, healthy
decortication of
Eucalyptus grandis outer bark
A
decorticating machine collecting fiber from leaves
Decussate phyllotaxis of
Crassula rupestris
Dentate leaf of
elm
Denticulate leaves of
Ziziphus mauritiana
Astragalus austriacus is regarded as
diadelphous because it has one stamen unattached to the main
adelphia (bunch).
The paired
cotyledons of a castor bean seedling (
Ricinus communis) are typical of a
dicotyledon.
Discolorous leaves of
Brachylaena discolor differ in color between their upper and lower surfaces.
Disk florets opening in a
capitulum of a cultivated
Helianthus. They open progressively from the edge to the center of the disk.
Dissepiment developing in tissue of
carpels where they meet to form
locules in the capsule of the ovary of
Lilium
Boophone disticha has conspicuously
distichous leaves.
Domatia at the bases of the thorns of
Vachellia drepanolobium, the whistling thorn, with visible access holes
Dorsiventral (bilateral) leaves of
Syzygium gerrardii and
Triadica sebifera
Leaves of
Epipremnum aureum (golden pothos) have a
cuspidate drip tip.
deciduous
Dehiscing and falling seasonally, as with
bark,
leaves, or
petals. Contrast
persistent.
declinate
Curving downward, and then upward at the tip. Often qualified, e.g. declinate-ascendant.
decompound
Divided to more than one level, e.g. in
bipinnate leaves, in which the
leaflets of what would otherwise be a
pinnate leaf are themselves pinnately divided.
decorticate
1. (intr. v.) To shed the outer bark of a tree, usually seasonally as part of the natural growth cycle.
2. (tr. v.) To strip the peel, crust, bark, or other surface tissues from a plant or from harvested material, such as in extracting fiber from harvested Agave leaves.
decumbent
Having branches growing horizontally along the ground but which are turned up at the ends.
decurrent
Extending downward beyond the point of
insertion, e.g. when the base of a leaf or a fungal gill is prolonged downward along the
stem in a raised line or narrow wing.
decussant
A synonym of
decussate; the usage decussant is questionable and occurs rarely, probably as an error. The formally correct usage is
decussate.
decussate
Opposite with successive pairs borne at right angles to the last; generally applied to the
arrangement of leaves.
definite
Of a constant number, e.g. twice as many
stamens as
petals or
sepals (or less), or an
inflorescence ending in a
flower or an aborted floral
bud, typically a
cymose inflorescence. Contrast
indefinite.
deflexed
Bent downward. Contrast
inflexed.
dehiscent
Breaking open at maturity to release contents; refers e.g. to the opening of
fruits to release
seeds, of
anthers to release
pollen, and of
sporangia to release
spores. Contrast
indehiscent.
deltoid
Shaped like the uppercase Greek letter Δ, i.e. like a more or less equilateral triangle.
dendroid
Tree-like; branching like a tree.
dentate
Toothed, especially in reference to
leaf margins.
denticulate
Finely
toothed; a diminutive form of
dentate.
deserticolous
Inhabiting a desert.
determinate
Limited, usually in growth. Contrast
indeterminate.
diadelphous
Referring to a class of
adelphous structure in which the
stamens or similar organs are connected in two
adelphiae instead of just one.
diaspore
Any reproductive part of a plant adapted for dispersal and for establishing new plants; may be a disseminule such as a
seed, or other parts such as specialized
buds, branches, inflorescences, or fruits.
dichasium
A
cymose inflorescence with all branches below the terminal flower in
regular opposite pairs. Compare
monochasium and
pleiochasium.
dichlamydeous
Having a
perianth which is divided into a separate
calyx and
corolla. Compare
homochlamydeous.
dichotomous
Forking into two equal branches. This may result from an equal division of the growing tip, or may be
sympodial, in which the growing tip is aborted and replaced. Typically refers to mode of branch growth, as in
Aloidendron dichotomum, but also to other organs, such as the
venation patterns on leaves, the thorns of various species of
Carissa (which morphologically are branches), and the
thalli or
hyphae of various algae and fungi.
dicotyledon
A flowering plant whose embryo has two or more
cotyledons (seed leaves). Contrast
monocotyledon.
digitate
With segments spreading from a common center, like the fingers of a hand. See also
palmate and
palmatisect. See also
Leaf shape.
digitiform
Shaped like a finger.
dimorphic
Occurring in two different forms (with respect to shape and/or size), e.g. of
stamens,
fronds, or leaves. See also
monomorphic (having a single form) and
polymorphic (having many forms).
dioecious
(of vascular plants) Having male and female reproductive structures which develop only on different individuals and never on the same individual. Contrast
monoecious.
dioicous
(of a
bryophyte gametophyte) Having male and female reproductive structures which develop only on different individuals and never on the same individual. Contrast
monoicous.
diploid
Having two complete sets of
chromosomes in the nucleus of a
sporophyte cell, i.e. one set from each of the parental
gametes. This is often expressed symbolically as 2n, where n = the number of chromosomes in the
haploid gamete.
diplostemonous
Having
stamens arranged in two
whorls, with the outer whorl alternating with the
petals while the inner whorl is opposite the petals. Compare
obdiplostemonous and
haplostemonous.
disc
A plate or ring of structures derived from the
receptacle, and occurring between
whorls of floral parts. In some groups, especially
Sapindales, the
nectary is in the form of a prominent disk. In
daisies, the central part of the
capitulum is a disk, hence flowers borne there are called
disk flowers or florets.
discoid
Resembling a disc or plate, having both thickness and parallel faces and with a rounded margin. Also used to describe the flower
head of
Asteraceae where there are no ray florets but only disc florets.
discolorous
(of
leaves) Having upper and lower surfaces of different colors.
disjunct
Occurring in widely separated geographic areas, distinctly separate; applies to a discontinuous range in which one or more populations are separated from other potentially interbreeding populations with sufficient distance so as to preclude gene flow between them.
disk floret
A
floret occurring most typically in the
disk of the
capitulum of flowers in the family
Asteraceae, and to some extent in other plants that bear a flowering head with a disk, such as
Scabiosa.
dissected
Deeply divided; cut into many segments.
dissepiment
A partition or
septum in a plant part, usually referring to septa between the
loculi of
capsules or of other fruits with multiple partitions.
distal
Remote from the point of origin or attachment; the free end. Contrast
proximal.
distichous
Arranged in two opposite rows (and hence in the same plane).
distinct
Separate or free; not united.
distyly
The condition in which the flowers of a species occur in two forms that differ only by the length of the
style and
stamens, and flowers of only one of these forms appear on any one plant. Compare
heterostyly.
diurnal
Of the day; occurring or opening in the daytime.
divaricate
Wide-spreading.
divergent
Spreading in different directions, generally upward.
division
A taxonomic rank below
kingdom in the standard taxonomic hierarchy. "Division" is generally used only for plants, and is the approximate botanical equivalent of the term
phylum, which is used for animals and other kingdoms.
domatia
Any hollow structure formed by a plant that is inhabited by animals such as ants or mites.
dorsal
From Latin dorsum, a ridge or the back of an animal. Partly because the term originally referred to animals rather than plants, usage in botany is arbitrary according to context and source. In
general "dorsal" refers to "the rear or back or upper surface", but in
botanical usage such concepts are not always clearly defined and may be contradictory. For example:
- facing away from the axis (abaxial) in a lateral organ of an erect plant
- facing away from the substrate in any part of an erect plant, for example the upper surface of a more or less horizontal leaf (adaxial) or the upper part of the crown of the plant
- facing away from the substrate in a prostrate or climbing plant or floating leaves such as those of Nymphaea.
Derived or related terms include
dorsad, "toward the dorsal", and
dorsum, "the dorsal part of the organ or organism as a unit". Related
anatomical terms of location include
ventral,
lateral.
dorsifixed
Attached at or by the back, e.g.
anthers on a
filament.
dorsiventral
Having structurally and visibly different upper and lower surfaces, e.g. some leaves. Compare
bilateral and
isobilateral.
drip tip
A long, narrow,
acuminate,
caudate, or
cuspidate extension at the tip of a
leaf or
leaflet. Commonly an adaptation to rainy conditions, as it promotes shedding of water by its dripping from the narrow tip. The term drip tip is not anatomically descriptive in the way that acuminate or cuspidate are, for example; rather, it is a description of the functional shape that aids dripping, regardless of the specific geometry of the shape itself.
drupe
A type of
succulent fruit formed from one
carpel; the single
seed is enclosed by a stony layer of the fruit wall, e.g. in peaches and olives. Also called a
kernel.
drupelet
A small
drupe formed from one of the carpels in an
apocarpous flower. Drupelets usually form a
compound fruit, as in
Rubus, but they may become widely separated, as in
Ochna.
druse
A globular mass of
calcium oxalate crystals, usually with the crystals radiating from an
organic core.
E
Plants of the genus
Corydalis bear seeds with attached
elaiosomes, which have various functions, commonly attracting ants. On some Corydalis species, elaiosomes that attract ants also repel mice.
Ficus lyrata is an example of a doubly-emarginate leaf with lateral and apical emargination; it also might be seen as a basally emarginate.
Petals of
Heracleum sphondylium are variously
emarginate at their tips. Flowers in the middle of the inflorescence have slightly emarginate petals, whereas flowers at the periphery are so deeply emarginate as to be almost cleft in two.
The pale
embryo emerging from the upper surface of the sprouting
date seed is tiny in comparison to the
endosperm, its main food supply, which comprises almost all of the rest of the seed.
Water lilies and
reeds represent two ecological categories of
emergent aquatic vegetation.
Iris pseudacorus has clearly
ensiform leaves: narrow, straight-edged, sword-shaped.
The enlarged
calyx and smaller
epicalyx of
Hibiscus sabdariffa
Shoots from
epicormic buds on
Eucalyptus following a
bushfire
Tillandsia recurvata growing as a harmless, non-parasitic
epiphloedal epiphyte on a tree trunk that is also infested with an epiphloedal
foliose lichen
Seeds or fruits are dispersed by
epizoochory when they stick to the fur of animals.
The bases of
equitant leaves enclose later leaves on the stem.
Sections of
exalbuminous seeds
Aloe marlothii flowers with stamens and stigmata of mature flowers
exserted from the mouths of the
floral tubes
-eae
A suffix added to the stem of a
generic name to form the name of a
tribe, e.g.
Aster →
Astereae.
ebracteate
Lacking
bracts;
synonymous with ebracteolate.
ecological amplitude
The range of environmental conditions in which an organism can survive.
edaphic
Of or influenced by the soil.
eglandular
Not having glands.
elaiosome
An external structure attached to the
seed of many species of plants. Elaiosomes generally look fleshy and in some species they are rich in oils or other nutritious materials. Their functions vary and are not always obvious; commonly they attract ants or other animals that aid in dispersal, but they may also repel other animals from eating the seed.
elephophily
A form of
pollination whereby
pollen or
spores are distributed by the feet of elephants, as in
Rafflesia arnoldii.
ellipsoid
A three-dimensional shape that is
elliptical in all sections through the long axis.
elliptical
Planar, shaped like a flattened circle, symmetrical about both the long and the short axis, tapering equally both to the tip and the base;
oval.
emarginate
Typically in reference to leaf margins: notched or recessed at some part of the edge, such as the
apex; the recess usually is broad and shallow. The location of a leaf's emargination(s) might be one or more of apical, lateral or basal
embryo
The young plant contained by a
seed prior to
germination.
emergent
A plant taller than the surrounding vegetation or, among aquatic plant species, one that bears
flowers and commonly
leaves above the surface of the water. Aquatic examples include water lilies, reeds, and
papyrus. Some pondweeds such as
Stuckenia are not emergent until they flower, at which time only their flowers appear above the water surface.
enation
Leaf-like outgrowth from a surface.
enantiostyly
The condition in which the
gynoecium protrudes laterally, to the right (
dextrostyly) or to the left (
sinistrostyly) of the
androecium, e.g.
Senna.
endemic
Having a natural distribution restricted to a particular geographic region. Compare
native.
endocarp
The innermost layer of the wall of a fruit; in a
drupe, the stony layer surrounding the seed.
endodermis
The innermost layer of the
cortex of
vascular plant roots, also present in the stems of
pteridophytes. The radial walls are impregnated with
suberin to form a permeability barrier known as the
Casparian strip.
endosperm
1. (
angiosperms) A
nutritive tissue surrounding the
embryo of the
seed, usually
triploid, originating from the fusion of both
polar nuclei with one
gamete after the fertilization of the egg.
2. (
gymnosperms) The
prothallus within the
embryo sac.
endospory
The production of
spores that germinate into a reduced multicellular
gametophyte contained within the spore wall. Contrast
exospory.
ensiform
Shaped like the blade of a sword.
entire
1. Not divided.
2. (of a
margin) Smooth and not
lobed or
toothed (though possibly wavy or
scalloped). See also
entire in Glossary of leaf morphology
entomophily
A form of
pollination whereby
pollen or
spores are distributed by
insects.
epecophyte
Species of recent appearance, usually numerous and constant in the country, but confined to artificial habitats, such as meadows and
ruderal vegetation and are dependent on humans for existence.
ephemeral
Short-lived. See also
caducous.
epicalyx
An
involucre resembling an outer
calyx, e.g. as in
Hibiscus.
epicarp
The outer layer of the wall of a
fruit, i.e. the "skin".
epicormic
Used to refer to
buds,
shoots, or
flowers developing from the old wood of trees, especially after injury or fire.
epicotyl
The part of the plant axis or stem between the
cotyledonary node and the first foliage leaves.
epicuticular wax
A layer of crystalline or amorphous
wax deposited on the surface of the
cuticle.
epidermis
An organ's outermost layer of cells, usually only one cell thick.
epigynous
Borne on the
ovary; describes floral parts when attached above the level of the ovary and arising from tissue fused to the ovary wall. Compare
hypogynous and
perigynous.
epilithic
Growing on stone. Compare
lithophytic, a plant growing on stone.
epipetalous
Of
stamens that are attached to the
petals.
epipetric
Growing on rock or stone,
lithophytic,
epilithic.
epiphloedal
Growing on the surface of
bark. Contrast
endophloedal (growing inside, not on, the bark) and
epilithic (growing on rock, not bark).
epiphyte
A plant, alga or fungus that grows on another plant without deriving nourishment from it but using it for support.
epiphytic
Of an
epiphyte; living on the surface of a plant. Compare
epilithic,
lithophytic.
episepalous
Of
stamens that are attached to the
sepals.
epitepalous
Of
stamens that are attached to the
tepals.
epithet
The adjectival component in a binomial scientific name, usually more specifically called a
specific epithet; the final word or combination of words in a name of more than one word (other than a term denoting rank) that denominates an individual taxon. The simplest and commonest example is the second word in a two-word name of a species, such as "mirabilis" in
Welwitschia mirabilis.
epizoochory
A type of
seed dispersal that occurs when seeds or
fruits physically adhere to the outside of vertebrate animal bodies.
epruinose
Not
pruinose.
equitant
(of a
leaf) Folded lengthwise and clasping another leaf.
erect
Upright, more or less perpendicular to the ground or point of attachment. Compare
patent (spreading) and
erecto-patent, between erect and patent.
ericoid
Having leaves like those of the European heaths (
Erica); small and sharply pointed.
erose
(of a
margin) Irregular as though nibbled or worn away.
ethelochoric
Deliberate introduction by seedlings, seeds or plants in a new habitat by humans.
etiolation
Weak growth due to lack of light, resulting in elongated stems and yellowish color.
even-pinnate
Having an even number of
leaflets in a
compound leaf;
synonymous with
paripinnate.
evergreen
Not
deciduous; having leaves all year.
ex
In nomenclature, indicating that the preceding author proposed the name but did not legitimately publish it, and that the succeeding author referred to the first author when legitimately publishing the name. See
Author citation (botany).
exalbuminous
In seeds of a given species, having no
endosperm, i.e. no
albumen, e.g. in
Fabaceae and
Combretaceae.
exocarp
The outer layer of the
pericarp, often the skin of fleshy
fruits.
exospory
The production of
spores that germinate into free-living multicellular
gametophytes. Contrast
endospory.
exotesta
The outer layer of the
testa (seed coat). It is derived from the outer
integument of the
ovule.
exotic
Not native; introduced from another region or country.
exserted
Projected beyond, e.g.
stamens beyond the
corolla tube.
exstipulate
Lacking
stipules.
extrastaminal
Outside the
stamens or
androecium, usually referring to the location of a nectary disk.
extrorse
(of
anther locules) Opening toward the outside of the
flower. Contrast
introrse and
latrorse.
F
Astragalus falcatus has conspicuously
falcate pods; not many falcate anatomical structures are so markedly curved.
Rhigozum obovatum bears its leaves in well-defined
fascicles.
Trunks and branches of some species of poplars contribute to the trees' fastigiate
habit.
Favolaschia calocera, the orange pore fungus, has conspicuously
faveolate fruiting bodies.
Emerging leaves of
Oldenburgia grandis are heavily
felted.
Fenestrate leaves of
Darlingtonia californica
In the wild, the leaves of
Fenestraria commonly are covered in soil, except for the transparent
fenestration; this permits
photosynthesis while reducing damage from exposure to intrense sunlight and herbivores.
Digitalis ferruginea owes its specific name to its
ferruginous (rust-colored) flowers.
Calochortus fimbriatus has
fimbriate flowers.
Panaeolus cinctulus has gently
flexuous stipes.
The
pseudanthium of
Zinnia elegans is typical of many
Asteraceae in that it includes two types of
florets,
ray florets and
disk florets.
Medicago sativa (
alfalfa or lucerne) is an agriculturally important
forb, grown in large volumes for forage, soil improvement, and other purposes.
Foveolate seeds of
Physochlaina physaloides
F1 hybrid
A single
cross; a plant breeding term for the result of a repeatable cross between two pure bred lines.
F2 hybrid
A plant breeding term for the result of a plant arising from a
cross between two
F1 hybrids; may also refer to
self-pollination in a population of F1 hybrids.
fabiform
Shaped like a
kidney bean.
facultative
Able to perform a particular life function, or to live generally, in more than one way.
Compare
obligate.
falcate
Curved like the blade of a
scythe.
family
A taxonomic group of one or more
genera with features, ancestry, or both in common. It is the term for the principal rank between
order and genus.
farina
Powdery, pale yellow, crystalline secretion consisting of
flavonoids in
Primula and other species.
farinaceous
Powderiness that is mealy.
fascicle
A cluster of flowers, leaves, needles,
vascular tissue, etc., e.g. a tuft of leaves all arising from the same node.
fasciculate
Branching in clusters, e.g. a bundle of sticks or needles; having
fascicles.
fastigiate
1. In
Plant morphology, the
habit of a plant that consists in part, of a bundle of erect, more or less parallel branches or stems, particularly if they form or taper to a peak or point. (Latin fastigiatus,meaning "having a peak".
2. In
palynology, the form of a pollen grain that has a
fastigium, a pointed apex over a hollow between the layers of the pollen outer wall.
faucal
Pertaining to the
fauces; located in the throat of a
calyx or
corolla.
fauces
The throat of a
calyx or
corolla; the conspicuously widened portion between the mouth and the
apex of the tube. In
Boraginaceae, the site of distinctive appendages.
faveolate
Honeycombed; having regular, angled
pits. Compare
foveolate.
felted
Having interlocked hairs to the extent of being matted.
female flower
See
pistillate flower.
fenestrate
Having
translucent or transparent areas that let light through; this variously affects the behavior of animal visitors or permits photosynthesis in many arid-region plants that grow only to the soil surface. Also refers loosely to perforations, for which
perforate is the more precise term.
ferruginous
Ruddy or
rust-colored.
fertile
Capable of producing fruit; of flowers when they produce seed, or of anthers containing pollen.
fertilization
The union of male and female
gametes during sexual reproduction.
fiber
1. A fiber cell.
2. Any flexible, strong, stringy, and very elongate structure.
fiber cell
A type of cell that is found in
sclerenchyma; it is much elongated, and dies soon after an extensive modification of its
cell wall. The cell wall is usually thickly
lignified but is sometimes
gelatinous.
filament
1. The stalk of a
stamen.
2. Any very narrow, thread-like structure that is one or a few cells thick.
filamentous
Consisting of
filaments or
fibers; hairlike.
filiform
Thread-like, e.g.
stamen filaments or
leaf shapes.
fimbria
Slender, hair-like projection; fringe.
fimbriate
Fringed, e.g. where the ends of a petal are split into two or more divisions.
Having
fimbriae.
fissure
A split or crack, often referring to fissured bark; a line or opening of
dehiscence.
fistule
A tube-shaped cavity.
fistulose
Hollow; usually applied to a tube-shaped cavity, as in a
reed.
flabellate
Fan-shaped, e.g. a flabellate (fan-shaped) leaf.
flaccid
Limp; tending to wilt. Compare
turgid.
flexistyly
Depending on the degree of maturation of the
stamens, the
style moves up or down (cataflexistyle or (ana-)hyperflexisyle).
flexuous
flexuose
Bent alternately in different directions;
zigzag.
floccose
Having a soft and wooly covering of hairs.
flora
1. All the plants growing in a certain region or country.
2. An enumeration of them, generally with a guide to their identification (e.g. the
Flora of North America,
Flora of China, Flora of Victoria, Flora of New South Wales, and so on). In this case, flora is written with a capital F.
floral envelope
See
perianth.
floral leaves
The upper leaves at the base of the flowering branches.
floral diagram
A graphical means to describe flower structure, usually a schematic cross-section through a young flower.
floral formula
A description of flower structure using numbers, letters, and various symbols.
floral tube
An imprecise term sometimes used as a
synonym of
hypanthium,
corolla tube, or
calyx tube.
floret
A small
flower, usually referring to the individual true flowers clustered within an
inflorescence, particularly those of the
Poaceae grasses and the
pseudanthia of family
Asteraceae.
flower
The sexual reproductive structure of the
angiosperms, typically with a
gynoecium,
androecium,
perianth, and an
axis.
foliate
Preceded by a number to signify having a certain number of leaflets, e.g. 3-foliate means "having three leaflets".
foliicolous
A growth habit of certain
lichens,
algae, and
fungi that prefer to grow on the leaves of
vascular plants.
follicle
A dry fruit formed from one
carpel splitting along a single
suture to which the seeds are attached, e.g. from the
pod of a
legume.
foliole
A small, leaf-like appendage on the front or back.
foliose
Leaf-like; flattened like a
leaf.
forb
Any non-woody
flowering plant that is not a
grass,
sedge, or
rush.
forest
Vegetation dominated by trees with single trunks, including closely arranged trees with or without an understory of shrubs and herbs.
forma (in common usage,
form)
A taxonomic category subordinate to species and within the taxonomic hierarchy, below
variety (
varietas), and usually differentiated by a minor character.
foveolate
Having regular tiny
pits. Compare
faveolate.
free
Not united with other organs of the same type; not attached at one end.
free central
(of
placentation)
Ovules attached to a free-standing column in the center of a
unilocular ovary.
frond
A
leaf of a
fern,
cycad, or
palm.
frutescent
Shrub-like (
fruticose) or becoming shrub-like.
fruticose
Shrubby; having the branching character of a
shrub.
fruit
A seed-bearing structure, present in all
angiosperms, formed from the mature
ovary and sometimes associated floral parts upon
fertilization.
fugacious
Disappearing, falling off, or withering. Compare
persistent and
caducous.
funicle (funiculus)
The stalk of an
ovule.
funnelform
Having a form gradually widening from the base to the
apex; funnel-shaped.
furcate
Forked, usually applied to a
terminal division; with two long
lobes.
fused
Joined together.
fusiform
Rod-shaped and narrowing gradually from the middle toward each end; spindle-shaped.
G
Galbulus (berry-like, fleshy) cones on the
coniferous tree
Podocarpus elatus
Gametophores (red male
antheridia and brown female archegonia) borne on a
gametophyte of a
Chara species of
green algae
Longitudinal section of immature male pine cone, showing male
gametophytes (pollen grains) developing between the cone scales
Glandular hairs on the stem of
Geranium dissectum
The leaves, buds, and young stalks of
Eucalyptus macrocarpa are
glaucous, covered with a thick waxy
pruinosity.
Glochids at the base of an
Opuntia cactus spine
Glumes of a grass species with a fairly large inflorescence
Scanning electron micrograph of a
stoma on the leaf of
Haemanthus. The two lip-shaped cells on either side of the pore are the
guard cells.
Drops of
guttation fluid on the
dentate points fringing the immature leaf of a grapevine
Examples of
gymnosperms LEFT
1-
Welwitschia mirabilis 2-
Cycas revoluta 3-
Taxus baccata 4-
Ginkgo biloba RIGHT
1-
Cupressus sempervirens 2-
Sequoiadendron giganteum 3-
Agathis dammara 4-
Araucaria heterophylla
galbulus
In
gymnosperms, a fleshy cone (
megastrobilus); chiefly relates to cones borne by
junipers and
cypresses, which are often mistakenly called
berries.
galea
An overhanging, helmet-shaped, structure that protects the reproductive parts from precipitation, wind or unwanted visitors.
gall
Abnormal outgrowth on external plant tissues, caused by various parasites, from viruses, fungi and bacteria, to other plants, insects and mites.
gamete
A cell or nucleus that fuses with another of the opposite sex during sexual reproduction.
Specialized structures on the
gametophytes of some
bryophyte species, for example many species in the order
Marchantiales; in such species the gametes are produced on the gametophores.
The
haploid multicellular phase in the
alternation of generations of plants and algae that bears
gametes. In
bryophytes the gametophyte is the dominant vegetative phase; in ferns and their allies it is a small free-living plant known as the prothallus; in gymnosperms and angiosperms the gametophytes are reduced to microscopic structures dependent on the
sporophyte, male gametophytes contained in
pollen grains and females contained within the
ovules.
gamopetalous
with joined or fused petals
gamophyllous
a single perianth-whorl of united segments. Compare
symphyllous (
synonym),
apophyllous, and
polyphyllous.
gemma
an asexual reproductive structure found in
liverworts and
mosses.
gene pool
The complete range of genetic variation found within a population.
genus
A group of one or more
species with features or ancestry (or both) in common. Genus is the principal category of taxa intermediate in rank between
family and species in the standard nomenclatural hierarchy.
generic name
The name of a taxonomic
genus, such as
Acacia and
Eucalyptus.
genotype
The genetic make-up of an individual.
geophilous
Growing or rooting in the ground.
germination
1. of seeds, describing the complex sequence of physiological and structural changes that occur from resting to growth stage.
2. of a pollen grain; production of a pollen tube when contacting a stigma receptive to it.
3. of a spore of fungi/bacterium; change of state – from resting to vegetative.
gibbous (gibbose)
(of part of an organ) Swollen, usually with a pouch-like enlargement at the base.
glabrescent
Becoming
glabrous, almost glabrous; glabrate.
glabrous
Lacking surface ornamentation such as hairs, scales or bristles; smooth.
gland
A secretory structure within or on the surface of a plant.
glandular hair
A hair tipped with a
gland.
glaucous
Describing the external surface of a plant part that has a whitish covering, in some cases with a blueish cast. Often applied to plants with a wooly or
arachnoid surface, but properly referring to
pruinose surfaces, meaning those with a waxy
bloom. The surfaces of the young leaves of many
eucalypts provide good examples, and so do some
xerophytes.
globose
Roughly spherical. See also
subglobose.
globulose
Approximately spherical.
glochid
A tiny barbed hair or bristle, e.g. the fine defensive hairs in cactus species such as
Opuntia.
glumes
bracts subtending the floret(s) of a
sedge, or similar plant; in
grasses forming the lowermost organs of a
spikelet (there are usually 2 but 1 is sometimes reduced; or rarely, both are absent).
glutinous
Sticky.
graft
1. The artificial union of plant parts.
2. A plant
shoot suitable for grafting; loosely, a
scion,
sucker, or branch.
graft chimaera (sometimes graft hybrid)
A taxon whose members consist of tissue from two or more different plants in intimate association originated by grafting. The addition sign "+" is used to indicate a graft-chimaera either as a part of a formula (e.g.
Crataegus monogyna +
Mespilus germanica) or in front of an abbreviated name (e.g.
+ Crataegomespilus 'Dardari'). The nomenclature of graft hybrids is governed by the
International Code of Nomenclature for Cultivated Plants.
graminaceous
Of or relating to grass.
graminoid
An herbaceous plant with a grass-like morphology.
granular
(of a surface) Covered with small rounded protuberances.
grass
A plant of the family
Poaceae.
grassland
Low vegetation dominated by
grasses.
groundcover
1. Dense vegetation that covers the ground.
2. A term applied to describe a plant that covers the soil surface so densely that it smothers all beneath it.
group
A formal category equivalent to or below the rank of
genus which distinguishes
- an assemblage of two or more cultivars within a species or hybrid;
- plants derived from a hybrid in which one or more of the parent species is not known or is of uncertain origin; or,
- a range of cultivated plants of a species or hybrid which may exhibit variation but share one or more characters, which makes it worth distinguishing them as a unit.
guard cell
Each of two cells surrounding the
stoma which control gas exchange between the
apoplast of the plant and the external environment.
guttate
Having droplet-shaped spots. Compare
punctate and
maculate.
guttation
The secretion of liquid water from uninjured plant parts. See
hydathode.
guttulate
Having or appearing to be spotted with oil droplets; of spores, having oil droplets inside.
gymnosperm
A seed-bearing plant with unenclosed ovules borne on the surface of a
sporophyll. Gymnosperms are among the oldest clades of vascular plants, and today are represented by approximately 1,000 extant species worldwide, including, among others,
conifers,
Ginkgo,
Gnetum and
cycads. Compare
angiosperm.
gynaecium
Alternative term for
gynoecium, but with partly different etymology.
gynobasic
Of a style, arising near the base of the
gynoecium, e.g. between the lobes of the
ovary.
gynodioecious
Of a species, with some plants bearing only
bisexual flowers and others bearing only female flowers.
gynomonoecious
Of a species, with
bisexual flowers and female flowers on the same plant.
gynoecium
The collective term for the female reproductive parts of a flower or for the
carpels of a flower, whether united or free. Contrast
androecium. Abbreviation: G. For instance, G indicates a
superior ovary; G(5) indicates having five fused carpels.
gynophore
A stalk supporting the
gynoecium and situated above the level of
insertion of the other floral parts.
gynostegium
A compound organ in milkweeds (
Asclepiadaceae) and
orchids formed by fusion of the
filaments of the
stamens with the
style. Also known as the
column.
H
Epidermal
hairs on plant leaves
Multicellular hairs on the edge of a sepal of
Veronica sublobata
Haplostemonous arrangement of
stamens and
petals
Markedly
hastate leaf of
Salvia canariensis
The swollen
haustorium of Viscum capense renders the end of the branch stunted compared to the lower part of the branch.
The fruit of
Poncirus is a typical hesperidium.
Heteroblastic growth is common in Eucalyptus species with leaves that are isobilateral in the mature tree; they generally start life with dorsiventral leaves. Some of these saplings are in the transient stage in which they have both forms of leaves, dorsiventral on lower branches, and isobilateral above.
The
hilum contrasts conspicuously with the rest of the
testa in the seeds of many species. In the case of Erythrina species, the colors may be a warning that the seeds are poisonous.
A
hypocarpium forms below the fruits of
Sassafras albidum.
Flowers, fruit and
propagule of a
Rhizophora "mangle" or
mangrove. The apparent root of the propagule is in fact
meristematic tissue developing from the
hypocotyl. The new plant develops largely from this tissue, especially if it has successfully penetrated into mud in which the new plant can establish itself.
habit
The general external appearance of a plant, including size, shape, texture, and orientation.
habitat
The place where a plant lives; the environmental conditions of its home.
hair
A single elongated cell or row of cells borne on the surface of an organ.
half-inferior ovary
An
ovary partly below and partly above the level of attachment of the other floral parts. Compare
inferior ovary and
superior ovary.
halonate
Having a transparent coating, or being of a spore's outer layer.
halophyte
A plant adapted to living in highly saline habitats; a plant that accumulates high concentrations of salt in its tissues.
hand-pollination
The controlled act of pollination that excludes the possibility of open-pollination.
haploid
Having one set of chromosomes, e.g. the complement of chromosomes in each of the cells of the
gametophyte, the nucleus of a
gamete, and the
spores. This is expressed symbolically as n, where n = the gametic number of chromosomes. Compare
diploid,
triploid, and
tetraploid.
haplostemonous
Having a single series of
stamens equal in number to the proper number of
petals, and alternating with them. Compare
diplostemonous and
obdiplostemonous.
harmomegathy
process by which pollen grains in arid environments close off their
apertures to avoid losing water
hastate
Triangular in outline, the basal lobes pointing outward, so that the base appears
truncate; may refer only to the base of a leaf with such lobes. Compare
sagittate, which refers to basal lobes pointing backward.
haustorium
In parasitic plants, a structure developed for penetrating the host's tissues.
head
See
capitulum, a
pseudanthium.
heathland
Vegetation dominated by small
shrubs which usually have
ericoid leaves.
helicoid
Coiled; of a
cymose inflorescence, when the branching is repeatedly on the same side (the apex is often
recurved). Compare
scorpioid.
heliophilous
Requiring or tolerating strong, direct sunlight.
hemerochory
A plant that has been transported voluntarily or involuntarily by humans in a territory which it could not have colonized by its own natural mechanisms of dissemination, or at least much more slowly.
hemi-legume
A legume fruit in which the seed or seeds and one valve of the pod are dispersed as a unit. The valve catches the wind and blows away with the seeds, as in
Acacia tenuifolia and
Peltogyne paniculata.
herb
Any
vascular plant that does not develop a
woody stem at any point during its life cycle, e.g. a
daffodil.
herbaceous
Not
woody; usually green and soft in texture.
herbarium
A collection of preserved, usually pressed and dried, plant material used for identification and comparison; also a building in which such collections are stored.
hermaphrodite
A
synonym of
bisexual.
hesperidium
A form of berry that occurs most familiarly in the genus
Citrus. The fruit tends to be large for a berry, ranging from not much more than a centimeter in small fruited genera such as
Murraya, to 15 cm or more in some varieties of
Citrus. The outer rind typically is thick and tough with many oil glands, while the carpels within are packed with juicy fibers.
heteroblastic
Having parts, especially leaves, that are distinctly different between the
juvenile and adult stages.
heteromorphic
Having two or more distinct morphologies (e.g. of different size and shape). Compare
isomorphic.
heterospory
The production of
spores of two different sizes (small and large) by the
sporophytes of land plants. Compare
homospory.
heterostyly
The condition of a species having flowers with different style and stamen lengths, but with all the flowers of any one plant being identical. See
distyly.
hilum
The scar on a seed coat where it separates from its stalk (
funicle).
hip
The fruit of a rose plant.
hippocrepiform
Horseshoe-shaped.
hirsute
Bearing coarse, rough, longish hairs. See
indumentum.
hispid
Bearing long, erect, rigid hairs or bristles, harsh to touch.
hoary
Covered with a greyish to whitish layer of very short, closely interwoven hairs, giving a frosted appearance.
holotype
A type chosen by the author of a name. Compare
lectotype.
homochlamydeous
Having a
perianth which is not divided into a separate
calyx and
corolla. Contrast
dichlamydeous.
homospory
The production of
spores of only one size by the
sporophytes of land plants. Compare
heterospory.
hort.
Of gardens, an author citation used in two ways:
1. as a name misapplied by gardeners
2. as an invalid name derived from horticultural writings of confused authorship.
husk
Protective outer covering of certain seeds, for example, the leafy outer covering of an ear of maize (corn), the leathery covering of the walnut, or the spiky covering of the chestnut.
hyaline
Translucent; usually delicately membranous and colorless.
hybrid
Plant produced by the crossing of parents belonging to two different named groups, e.g. genera, species, varieties, subspecies, forma and so on; i.e. the progeny resulting within and between two different plants. An
F1 hybrid is the primary product of such a cross. An F2 hybrid is a plant arising from a cross between two F1 hybrids (or from the self-pollination of an F1 hybrid).
hybrid formula
The names of the parents of a hybrid joined by a multiplication sign, e.g. Cytisus ardonoi × C. purgans.
hydrophily
Form of pollination whereby pollen is distributed by the flow of waters.
hypanthium
Tube or cup-like structure in a flower that includes the bases of sepals, petals, and stamens, and may or may not be connected (
adnate) to the
ovary.
hyper-resupinate
In
botany, describing leaves or flowers that are in the usual position but are borne on a
petiole or
pedicel that is twisted 360 degrees. The term is used to describe organs, such as orchid flowers, that are usually resupinate. Compare
resupinate.
hypocarpium
Enlarged fleshy structure that forms below the fruit from the
receptacle or
hypanthium.
hypocotyl
Of an embryo or seedling, the part of the plant axis below the
cotyledon and
node, but above the root. It marks the transition from root to stem development.
hypocrateriform
Salver-shaped.
Synonym of
salverform. From Greek kratḗrion: a vessel.
hypogynous
Borne below the ovary; used to describe floral parts inserted below the ovary's level of insertion. Compare
epigynous and
perigynous.
hysteranthous
Type of growth in which new leaves appear after flowering. Also spelled histeranthous. Compare
proteranthous and
synanthous.
I
Imbricate protective
cataphylls on dormant buds of
Quercus robur
Petals of
Mespilus germanica are imbricate before the flower opens.
Doubly
imparipinnate compound leaf of
Melia azedarach
Deeply
incised leaves of
Pelargonium graveolens
Indefinite stamens of
Hypericum
Indehiscent pods of
Libidibia ferrea; unlike most
Fabaceae species, the plant depends on the pods being crushed by large
ungulates to
disperse the seeds.
Aloe brevifolia bears an
indeterminate raceme.
The leaves of
Syagrus palms are '
induplicately folded, in contrast to many other palm genera with
reduplicate leaves.
Stamens of
Calotropis gigantea are
inserted at the base of the corolla.
The
intramarginal veins near the margins of this leaf are outlined in white.
Two of these three green
Asteraceae involucres encase unopened flower heads, and the third supports the open colorful head of emerging flowers. The imbricate
phyllaries around the heads of this
Malacothrix coulteri suggest the keeled scales of a snake, giving the plant its common name: "snake's head".
This
Begonia leaf shows unusual
iridescence for a plant.
idioblast
A cell, especially of a
leaf, differing markedly from surrounding cells. They often synthesise specialized products such as crystals.
illegitimate name (nomen illeg.)
A name not abiding by the rules of the botanical Codes, e.g. later
homonyms, cultivars that have been Latinised after 1 Jan 1959;
cultivar names with more than 10 syllables or 30 letters; cultivar names that use confusing names of other plants, e.g. Camellia 'Rose'.
imbricate
From the Latin for "tiled". Overlapping each other; of
perianth parts, edges overlapping in the bud (the convoluted arrangement is a special form of imbrication). Dormant buds of many
deciduous species are imbricately covered with protective cataphylls called bud scales. Compare with subimbricates meaning lightly overlapping
imparipinnate
A
pinnate leaf with an odd number of
pinnae (terminated by a single leaflet). Compare
paripinnate.
in
In nomenclature, where the preceding author published the name in an article or book, authored or edited by the succeeding author.
-inae
The suffix added to the stem of a
generic name to form the name of a
subtribe: for instance,
Corydalinae from
Corydalis + -inae.
inbreeding
The production of offspring between closely related parents leading to a high degree of similarity; self-fertilization is the most intense form of inbreeding.
incertae sedis
Of unknown taxonomic affinity; relationships obscure.
incised
Cut deeply and (usually) unevenly (a condition intermediate between toothed and lobed).
included
Enclosed, not protruding, e.g.
stamens within the
corolla.
incomplete flower
A flower which lacks one or more of its usual parts, such as carpels, sepals, petals, pistils, or stamens.
incurved
Bent or curved inward; of
leaf margins, when curved toward the
adaxial side.
ined.
An abbreviation of Latin inedita, an unpublished work. Used to indicate that a botanical name appeared only in a manuscript that was not published, so the name is invalid.
indefinite
variable in number, and as a rule numerous, e.g. more than twice as many stamens as petals or sepals, but no particular standard number of stamens. In another usage it is a synonym for the preferable term
indeterminate, meaning the condition in which an inflorescence is not terminated by a flower, but continues growing until limited by physiological factors. Compare
numerous. Contrast
definite.
indehiscent
Not opening in any definite manner at maturity; usually referring to
fruit. Contrast
dehiscent.
indeterminate
usually referring to a stem or inflorescence in which there is no particular terminal bud or
meristem that stops growth and ends the extension of the stem, which continues until physiological factors stop the growth. Racemes of some Xanthorrhoeaceae, such as many Aloes, and of many Iridaceae, such as Watsonias, are indeterminate. Contrast
determinate.
indigenous
Native to the area, not introduced, and not necessarily confined to the region discussed or present throughout it (hardly distinct from ‘native' but usually applied to a smaller area). For example, the Cootamundra Wattle is native to Australia but indigenous to the Cootamundra region of southern New South Wales. Compare
endemic.
indumentum
Collective term for a surface covering of any kind of
trichomes, e.g. hairs, scales.
induplicate
Folded upward, or folded with the two
adaxial surfaces together.
indusium
1. Membrane covering the
sori of some ferns.
2. Cup enclosing the stigma in
Goodeniaceae.
inferior ovary
An
ovary at least partly below the level of attachment of other floral parts. Compare
superior ovary and
half-inferior ovary.
inflated
Swollen, like a bladder.
inflexed
Bent sharply upward or forward. Compare
deflexed.
inflorescence
several flowers closely grouped together to form an efficient structured unit; the grouping or arrangement of flowers on a plant.
infraspecific
denotes taxonomic ranks below species level, for example subspecies.
infrageneric
denoting taxonomic ranks below the genus level, for example, subgenera, sections, and series.
infructescence
the grouping or arrangement of fruits on a plant.
infundibular (infundibuliform)
funnel-shaped, for example in the
corolla of a flower.
inrolled
rolled inward.
insectivorous
catching, and drawing nutriment from, insects.
insertion, point of
The point at which one organ or structure (such as a
leaf) is joined to the structure which bears it (such as a
stem).
inserted
growing out from
integument
in general, any covering, but especially the covering of an
ovule.
intercalary
(e.g. of growth) occurring between the apex and the base of an organ
intercalary meristem
a
meristem located between the apex and the base of an organ
interjugary glands
in pinnate leaves, glands occurring along the leaf
rachis between the
pinnae (occurring below the single, and often slightly larger, gland at or just below the insertion of the pinnae). Compare
jugary.
internode
The portion of a
stem between two
nodes.
interpetiolar
(of
stipules) Between the petioles of opposite leaves, e.g in
Rubiaceae.
intramarginal
inside but close to the margin. For example, an intramarginal
vein is one that parallels, and is very close to, the leaf margin.
intrastaminal
inside the stamens or
androecium, usually referring to the location of a nectary disk.
introrse
of
anther locules, with opening toward the center of flower (at least in bud). Compare
extrorse and
latrorse.
invalid
Use of names not validly published according to the Code, i.e. they are not strictly 'names' in the sense of the
International Code of Botanical Nomenclature.
involucre
A structure surrounding or supporting, usually a head of flowers. In
Asteraceae, it is the group of
phyllaries (
bracts) surrounding the inflorescence before opening, then supporting the cup-like receptacle on which the head of flowers sits. In
Euphorbiaceae it is the cuplike structure that holds the nectar glands, nectar, and head of flowers, and sits above the bract-like
cyathophyll structure. Involucres occur in
Marchantiophyta,
Cycads,
fungi, and many other groups.
involute
Rolled inward, for example when the margins of a
leaf are rolled toward the
adaxial (usually upper) surface. Compare
revolute.
iridescent
Having a reflective colored sheen produced by
structural coloration, as in the speculum of the mirror orchid Ophrys speculum.
irregular
Not able to be divided into two equal halves through any vertical plane. See also
asymmetrical. Compare
zygomorphic,
actinomorphic, and
regular.
isobifacial
(of flat structures, especially leaves) Having both surfaces similar, usually referring to cell types or to the number and distribution of
stomata.
isomerous
Having an equal number of parts in the
whorls.
isomorphic
with all features morphologically similar, i.e. of similar size and shape. Compare
heteromorphic.
isotomic
Having branches of equal diameter. Compare
anisotomic.
J
Vachellia karroo bipinnate leaf
A. Rachilla
B. Pinnule
C.
Jugary glands D. Juga (plural of
jugum)
E. Base of petiole
F. Petiolary gland
G. Rachis
Jugate leaf of Bauhinia glabra
Jugate fruit of
Tabernaemontana elegans
Eucalyptus camaldulensis has
dorsiventral juvenile leaves.
joint
A
node or junction of two parts;
articulation.
jugary
associated with a
jugum or something yoke-like; see for example
jugary gland.
jugary gland
A gland occurring on the
rachis of a
pinnate or
bipinnate leaf on a
jugum, the junction or attachment of pairs of
pinnae or
pinnules, as in some
Acacia species. Compare
interjugary.
jugate
yoke-like; describing a structure of paired items joined together as in a
jugum or something yoke-like, such as some leaves and fruit.
jugum
applied to various yoke-like organs, usually in the sense of their being paired, such as a pair of
pinnae on a
rachis.
juvenile leaves
Leaves formed on a young plant, typically differing from the adult leaves in form.
K
One form of the
kettle traps of a pitcher plant
Kidney-shaped leaf of
Cucurbita maxima
Typical
knee at a node in a grass stem
Unusually dense stand of
cypress knees around the parent tree
keel
A prominent longitudinal ridge like the keel of a boat, e.g. the structure of the
corolla formed by the fusion of the lower edge of the two abaxial anterior petals of flowers in the
Fabaceae.
kernel
See
drupe.
kettle trap
another term for the kettle-like pitchers of any of the carnivorous
pitcher plants, in which they trap their prey.
key innovation
A novel
phenotypic trait that allows subsequent
evolutionary radiation and success of a
taxonomic group.
kidney shape
A term describing a
kidney-shaped object such as a bean or a leaf; more formally,
oblately cordate, or
crescent-shaped with the ends rounded.
kingdom
the highest generally employed category of the taxonomic hierarchy, above that of division (phylum). The Plant Kingdom includes
vascular plants,
bryophytes and
green algae and is also known as the
clade Viridiplantae.
Klausenfrucht
Klausen or Klausenfrucht (german) is a special type of fruits in
Lamiaceae and
Boraginaceae. A dry, dehiscent fruit formed from a superior ovary with axil or basal placentation, with an adherent calyx, from more than one carpel and usually breaking apart into 1-seeded units by separating each carpel by false septa. One unit is a half carpel, mostly there are four units, seeds. English terms are eremocarp, schizocarp, mericarp or nutlets.
knee
abrupt bend in a root or stem, commonly at a
node; a
cypress knee, or
pneumatophore, is a type of bend or knob in the root of some plants, especially conifers such as some of the
Taxodioideae, that shows as a projection of the root above ground level or mud level.
L
Labiate flowers of
Prunella vulgaris
Laciniate, deeply incised, leaves of
Pelargonium crispum
Most
Euphorbias are laticiferous and instantly exude
latex when even mildly punctured.
A
leaf scar on
Juglans regia, showing the layer of corky protective tissue that remained after the leaf separated along the
abscission zone. It also shows the leaf traces of the
vascular bundles that broke off when the abscission zone failed. The
axillary bud associated with the leaf shows just above the scar.
The dark horizontal lines on
silver birch bark are
lenticels.
Lignotubers of
Lambertia formosa growing sprouts after a bush fire
Ligule between the leaf sheath and leaf of a grass
Loculicidal dehiscence of a fruit
capsule. The locule walls split at the back, and the valves separate, bearing the septa on their centers.
The
loment (or lomentum) of
Hedysarum occidentale splits into single-seeded segments along the visible lines of weakness when ripe.
labellum
lip; one of three or five petals which is (usually) different from the others, e.g. in
Orchidaceae,
Zingiberaceae,
Cannaceae and
Stylidiaceae.
labiate
lipped; where a
corolla is divided into two parts, called an upper and lower lip, the two resembling an open mouth with lips.
lacerate
jagged, as if torn.
laciniate
Of
lobes – with ends irregularly divided into deeply divided, narrow, pointed segments; Of
margins – deeply divided into pointed segments in an irregular manner.
lacuna
An empty space, hole, cavity, pit, depression, or discontinuity.
lamella
Thin, plate-like layer. Composed of an assemblage of many layers.
lamina
the blade of a leaf or the expanded upper part of a
petal,
sepal or
bract.
lanate
covered in or composed of wooly hairs.
lanceolate
longer than broad, narrowly ovate, broadest in the lower half and tapering to the tip, like a lance or spear head; (sometimes, and incorrectly, used to mean narrowly elliptic).
lanuginose
covered in long hairs that cross and/or interweave with each other. More commonly the term
lanate is used.
lateral
attached to the side of an organ, e.g. leaves or branches on a stem. For more detail see
dorsal.
latex
a milky fluid that exudes from such plants such as
spurges,
figs and
dandelions.
laticiferous
latex-bearing, producing a milky juice.
latrorse
a type of anther
dehiscence in which the
anthers open laterally toward adjacent anthers. Compare
introrse and
extrorse.
lauroid
resembling
Laurus, the laurel genus, particularly its leaves.
lax
loose, not compact.
leaf
an outgrowth of a stem, usually flat and green; its main function is food manufacture by photosynthesis. Abbreviation: lvs.
leaf gap
a
parenchymatous area in the
stele above (distal to) a
leaf trace.
leaf scar
A healing layer forming on a
stem where a
leaf has fallen off.
leaf trace
A
vascular bundle connecting the
stele to a
leaf.
leaflets
The ultimate segments of a
compound leaf.
legume
1. a fruit characteristic of the family
Fabaceae, formed from one carpel and either
dehiscent along both sides, or
indehiscent.
2. a crop species in the family Fabaceae.
3. a plant of the family Fabaceae.
lemma
the lower of 2
bracts enclosing a
grass flower.
lenticel
Typically
lenticular (lens-shaped)
porous tissue in bark with large
intercellular spaces that allows direct
exchange of gases between the internal tissues and atmosphere through the bark.
lenticellate
Having lenticels
lenticular
1. lens-shaped.
2. covered in
lenticels.
lepidote
covered with small scales.
leprose
powdery
liana
a woody climbing plant, rooted in the ground (
liane is also used).
liane
a woody climbing plant, rooted in the ground. See also
liana.
ligneous
having hard lignified tissues or woody parts, woody
lignum
Dead wood, typically in the context of a substrate for
lichens.
lignicolous
Growing on wood tissue after bark as fallen or been stripped off (compare to
corticolous).
lignotuber
a woody swelling of the stem below or just above the ground; contains adventitious buds from which new shoots can develop, e.g. after fire.
ligulate
1. bearing a
ligule.
2. strap-shaped.
ligule
1. A small membranous appendage on the top of the
sheath of grass leaves.
2. A minute
adaxial appendage near the base of a
leaf, e.g. in
Selaginella.
3. An extended, strap-like
corolla in some daisy florets.
linea, line, British line, Paris line
Various pre-metric units somewhat larger than 2 mm, used in botany into the 20th century. See
Line (unit) and
Paris line.
linear
Very narrow in relation to its length, with the sides mostly parallel. See
Leaf shape.
lingulate
tongue-shaped.
lip
A
labellum.
lithophytic
A plant growing on rocks; an
epilithic plant.
lobe
Part of a
leaf (or other organ), often rounded and formed by incisions to about halfway to the
midrib.
lobulate
Having, consisting of or relating to a lobe or lobes.
loculicidal
(of a fruit)
Dehiscing through the centers of
loculi. Compare
septicidal.
locule
A chamber or cavity containing seeds within an
ovary, pollen within an
anther or spores in a
sporangium.
lodicule
One of two or three minute organs at the base of the
ovary of a
grass flower, representing parts of a strongly reduced
perianth.
lomentum or loment
A pod-like
indehiscent fruit that develops constrictions between the segments and at maturity breaks into one-seeded segments instead of splitting open.
longicidal
(of
anthers) Opening lengthwise by longitudinal slits. Compare
poricidal.
lunate
Crescent-shaped.
lumen
The cavity bounded by a plant cell wall.
lyrate
Lyre-shaped; deeply lobed, with a large terminal
lobe and smaller lateral ones.
M
Maculate leaves
Eucalyptus socialis, showing its
mallee habit, a single tree with several trunks growing from an underground
lignotuber
Mast from beeches on the forest floor
Geranium incanum schizocarp and
mericarp
Apical
meristem in root tip:1: Meristem
2:
Columella showing
statocytes with statoliths3: Lateral part of the tip
4: Dead cells
5: Elongation zone
Mesophyll as seen in the cross section of a dicotyledonous leafA-Lower epidermis
B-Lower palisade mesophyll
C-Upper epidermis
D-Upper palisade mesophyll
E- Spongy mesophyll
F-Leaf vein
Longitudinal section of
Pinus ovuleA=
GametophyteB=Egg cell
C=
MicropyleD=Integument
E=
Megasporangium
Strobilus of a SelaginellaA-
MegasporeB-
MicrosporangiumC-
MegasporangiumD-
MicrosporeE-
Sporophyll
Moniliform pods on
Vachellia nilotica
A germinating
date palm, Phoenix dactylifera, a
monocotyledon, showing its single
cotyledon
Mucro at the tip of the
rachis of a compound leaf of
Vachellia karroo
Fungal
mycelium grown in culture dish
Mycelium of
mycorrhiza growing on the roots of
Picea
maculate
Spotted; marked with spots.
male flower
See
staminate flower.
mallee
A growth habit in which several woody stems arise separately from a
lignotuber; a plant with such a growth habit, e.g. many
Eucalyptus species; vegetation characterized by such plants.
mangrove
Any
shrub or small
tree growing in salt or brackish water, usually characterized by
pneumatophores; any tropical coastal vegetation characterized by such species.
margin
The edge of a structure, as in the edge of a
leaf blade.
marginal
Occurring at or very close to a
margin.
marsh
A waterlogged area or swamp.
mast
Edible fruit and nuts produced by woody species of plants (e.g.
acorns and
beechmast) which is consumed on the ground by wildlife species and some domestic animals.
mealy
Covered with coarse, floury powder.
medulla
pith. See also
medullary rays in wood.
megasporangium
the larger of two kinds of sporangium produced by
heterosporous plants, producing large spores that contain the female
gametophytes. Compare
microsporangium.
megaspore
the larger of two kinds of spores produced by a
heterosporous plant, giving rise to the female
gametophyte. Compare
microspore.
megasporophyll
in
hetersoporous plants, a modified leaf bearing one or more
megasporangia. Compare
microsporophyll.
megastrobilus
the larger of two kinds of cones or
strobili produced by
gymnosperms, being female and producing the seeds. Compare
microstrobilus.
membranous
thin, translucent and flexible, seldom green.
mericarp
one segment of a fruit (a
schizocarp) that splits at maturity into units derived from the individual
carpels, or a carpel, usually 1-seeded, released by the break-up at maturity of a fruit formed from 2 or more joined carpels.
meristem
Any actively dividing plant tissue.
mesic
Moist, avoiding both extremes of drought and wet; pertaining to conditions of moderate moisture or water supply; applied to organisms (vegetation) occupying moist habitats.
mesocarp
The fleshy portion of the wall of a
succulent fruit inside the skin and outside the stony layer (if any), surrounding the seed(s);
sarcocarp.
mesomorphic
Soft and with little fibrous tissue, but not
succulent.
mesophyll
1. The
parenchyma tissues between the upper and lower epidermis. They vary in function, but usually include the photosynthetic tissue of a
leaf.
2. In ecology, the blade of a leaf or
leaflet that has a surface area 4500–18225 mm2; a plant, or vegetation, that has mesophyll (sized) leaves.
mesophyllous
(of vegetation) Of moist habitats and having mostly large and soft leaves.
mesophyte
A plant thriving under intermediate environmental conditions of moderate moisture and temperature, without major seasonal fluctuations.
micropyle
Opening at apex of
ovule.
microsporangium
The smaller of two kinds of
sporangium produced by a
heterosporous plant, producing
microspores that contain the male
gametophyte. Compare
megasporangium.
microspore
The smaller of two kinds of spores produced by a
heterosporous plant. Compare
megaspore.
microsporophyll
In
heterosporous plants, a modified leaf bearing one or more
microsporangia. Compare
megasporophyll.
microstrobilus
The smaller of two kinds of cones or
strobilus produced by
gymnosperms, being male and producing the pollen. Compare
megastrobilus.
midrib
The central and usually most prominent
vein of a leaf or leaf-like organ.
midvein
See
midrib.
monad
A single individual that is free from other individuals, not united with them into a group. The term is usually used for pollen to distinguish single grains from
tetrads or polyads.
monadelphous
A term describing stamen filaments that are fused for the greater part of their length, forming a tube around the style.
moniliform
Resembling a string of beads.
monocarpic
Flowering and setting seed only once before dying. See also
semelparous.
monochasium
A
cymose inflorescence with the branches arising singly. Compare
dichasium and
pleiochasium.
monocot
An abbreviation of
monocotyledon.
monocotyledon
A flowering plant whose
embryo contains one
cotyledon (seed-leaf). Compare
dicotyledon.
monoecious
(of vascular plants)
Hermaphroditic, with all flowers
bisexual, or with male and female reproductive structures in separate flowers but on the same plant, or of an inflorescence that has
unisexual flowers of both sexes. Contrast
dioecious.
monoicous
(of
bryophyte gametophytes)
Hermaphroditic or
bisexual, where both male and female reproductive structures develop on the same individual. Contrast
dioicous.
monograph
Of a group of plants, a comprehensive treatise presenting an analysis and synthesis of taxonomic knowledge of that taxon; the fullest account possible (at the time) of a family, tribe or genus. It is generally worldwide in scope and evaluates all taxonomic treatments of that taxon including studies of its evolutionary relationships with other related taxa, and cytological, genetic, morphological, palaeobotanical and ecological studies. The term is often incorrectly applied to any systematic work devoted to a single taxon. Compare
revision.
monomorphic
Of one type, rather than several. See also
dimorphic (two types) and
polymorphic (many types).
monophyllous
Having a single
leaf.
monopodial
A mode of
stem growth and branching in which the main axis is formed by a single dominant
meristem. Contrast
sympodial.
monostromatic
Being a single cell thick, as in the
alga Monostroma.
monothecous
having a sole compartment or cell. Compare
Dithecous.
monotypic
Containing only one taxon of the next lower rank, e.g. a family with only one
genus, or a genus that includes only a single
species.
morphology
The shape or form of an organism or part thereof.
mucro
A sharp, short point, generally at the tip of a leaf or the tip of the midrib of a compound leaf.
mucronate
Terminating in a
mucro.
multiple fruit
A cluster of
fruits produced from more than one
flower and appearing as a single fruit, often on a swollen axis, as with many species of the family
Moraceae. Compare
aggregate fruit.
muricate
Covered with short, hard protuberances.
mutation
In times before the nature of genetic encoding was understood, mutation was regarded as an abrupt, and sometimes heritable, variation from the norm of a population; for example a plant might unexpectedly produce "double" flowers, a novel color, or a
habit of growth uncharacteristic of the species or variety. Advances in
genetics and
molecular biology in the mid-twentieth century, showed that
biological mutations comprise and reflect changes in the
nucleic acid molecules that
encode the
genome of an
organism or
virus. The nucleic acid affected could be
DNA in the chromosomes, or it could be
extrachromosomal DNA (typically DNA in the
mitochondria or
chloroplasts). In
RNA viruses a mutation would be a change to the genetic
information that the
RNA encodes.
mycelium
The "vegetative" (nonreproductive) part of a
fungus, mostly composed of aggregations of
hyphae. It functions in substrate decomposition and absorption of nutrients.
mycorrhiza
One of several types of
symbiotic association between a fungus and the roots of a plant.
mycotroph
A plant that obtains most or all of its carbon, water, and nutrients by associating with a
fungus.
N
Hoya carnosa secretes so much
nectar that it falls in drops if no pollinators remove it.
The small green petals of
Helleborus argutifolius act as floral
nectaries. The
sepals function as
petals.
Some
Senna species have extrafloral nectaries that attract ants to defend them from pests.
Plant stem
nodes and
internodes
native
Naturally occurring in an area, but not necessarily confined to it. Compare
endemic.
natural hybrid
A
hybrid taxon produced by chance in the wild.
naturalised
Describing a plant, introduced from another region, that grows and reproduces readily in competition with the natural flora.
nectar
A usually sweet, nutrient-rich fluid produced by the flowers of many plants and collected by bees and other
pollinators.
nectary
A specialized gland that secretes
nectar.
neophyte
A plant that has recently been introduced to a geographic area. Contrast
archaeophyte.
nerve
Another name for a
vein.
node
The part of a
stem from which leaves or branches arise.
nomen conservandum
(Latin) A conserved name, usually a name that became so much better known than the correct name, that a substitution was made.
nomen illegitimum
A name that is either superfluous at its time of publication because the taxon to which it was applied already has a name, or the name has already been applied to another plant (a homonym).
nomen invalidum
A name that is not validly published, and technically is therefore not a
botanical name. Abbreviation: nom. inval. See
valid publication.
nomen nudum
A name not published in accordance with the
International Code of Nomenclature for algae, fungi, and plants, usually without a diagnosis or description of the entity to which it applies, and without reference to either; such a name should not be used.
nomenclature
The naming of things; often restricted to the correct use of scientific names in taxonomy; a system that sets out provisions for the formation and use of names.
noxious
Of plants, containing harmful or unwholesome qualities. Applied in conjunction with 'weed' to specifically describe a plant which legislation deems harmful to the environment. Each state and territory in Australia has specific legislation governing noxious weeds.
nucellus
The tissue of the
ovule of a
seed plant that surrounds the female
gametophyte. It is enclosed by integuments and is not of
epidermal origin.
numerous
Stamens are described as numerous when there are more than twice as many as sepals or petals, especially when there is no set number of them. Compare
indefinite.
nut
A hard, dry,
indehiscent fruit containing only one seed.
nutlet
1. A small
nut.
2. One of the lobes or sections of the mature
ovary of some members of the
Boraginaceae,
Verbenaceae, and
Lamiaceae.
O
Obconical syconium (
infructescence) of
Ficus carica
Obcordate leaflets of a
ternate leaf of
Oxalis pes-caprae
Obovate leaflets of a
ternate leaf of
Kummerowia
Obtuse leaves of
Dovyalis zeyheri
Open flower of
Eucalyptus macrocarpa, next to a shed
operculum
Opposite arrangement (
phyllotaxis) of leaves
Orbicular leaves of
Dombeya rotundifolia
Ovate leaflets on a
ternate leaf of a
Vigna species
ob-
A prefix meaning "inversely"; usually the same shape as that described by the word stem, but attached by the narrower end. See
obcordate,
oblanceolate and
obovate.
obconic
(of a
fruit,
hypanthium,
pistil, or
calyx) Shaped like an inverted cone, attached at the apex.
obcordate
(of a leaf
blade) Broad and notched at the tip; heart-shaped but attached at the pointed end.
obdiplostemonous
Having
stamens arranged in two
whorls, and having twice as many stamens as
petals, with the outer whorl being opposite the petals. Compare
diplostemonous and
haplostemonous.
oblanceolate
Having a
lanceolate shape but broadest in the upper third.
oblate
Having a spherical shape but flattened at the poles.
obligate
(of parasites) Unable to survive without a host. Contrast
facultative.
oblique
Slanting; of a leaf or stem, larger on one side of the
midrib than the other, in other words
asymmetrical.
obloid
Having a three-dimensional
oblong shape, e.g. a fruit.
oblong
Having a length a few times greater than the width, with sides almost parallel and ends rounded.
obovate
(of a leaf) Having a length about 1.5 times the width, and widest above the center.
obsolete
Not evident, or at most
rudimentary or
vestigial.
obtrapeziform
trapeziform, but attached by the narrower trapezoidal base (e.g. of a leaf)
obtuse
Blunt or rounded; having converging edges that form an angle of more than 90°. Compare
acute.
ocrea
A
sheath formed from two
stipules encircling the
node in members of the
Polygonaceae.
odd-pinnate
Having an odd number of
leaflets in a
compound pinnate leaf, such that there is only one terminal leaflet.
oft.
An abbreviation of "often". Compare
usu. and
s.t..
-oideae
A suffix added to the stem of a
generic name to form the name of a
subfamily, e.g.
Fumaria →
Fumarioideae.
olim
Formerly, e.g. "olim B", formerly in the Berlin
herbarium (Herbarium Berolinense).
ontogeny
The sequence of developmental stages through which an organism passes as it grows.
operculum (calyptra)
A lid or cover that becomes detached at maturity, e.g. in
Eucalyptus, a cap covering the bud and formed by the fusion or cohesion of
perianth parts.
opposite
1. Describing leaves or flowers borne at the same level but on directly opposite sides of their common
axis.
2. Describing the occurrence of something on the same radius as something else, e.g.
anthers opposite
sepals. Compare
alternate.
opus utique oppressum
Listed after the botanical name of a plant, or the name of a publication, this indicates that a publication is listed in the
International Code of Nomenclature for algae, fungi, and plants as a suppressed work. Botanical names of the specified rank in the publication are considered not
validly published (article 34).
orbicular
Flat and more or less circular.
order
A group of one or more families sharing common features, ancestry, or both.
ortet
The original single parent plant from which a
clone ultimately derives.
orthotropous
Describes an ovule that is erect, with the
micropyle directed away from the placenta;
atropous. Compare
amphitropous,
anatropous, and
campylotropous.
oval
See
elliptical.
ovary
The basal portion of a
carpel or group of fused carpels, enclosing the
ovules.
ovate
Shaped like a section through the "long axis" of an egg and attached by the wider end.
ovoid
Egg-shaped, with wider portion at base; 3-dimensional object, ovate in all sections through long-axis.
ovule
Loosely, the seed before fertilization; a structure in a seed plant within which one or more
megaspores are formed (after fertilization it develops into a seed).
P
The thick trunk of
Brachychiton rupestris accumulates moisture as a means of survival of droughts, and presents a marked example of a
pachycaul habit.
This
Curio articulatus is
pachycladous in that it has a disproportionately thick stem.
A maple (
Acer platanoides) leaf has
palmate venation, as its veins radiate out from a central point, like fingers from the palm of a hand.
The
inflorescence of
Agave americana is a giant
panicle.
Asclepias physocarpa shedding seeds, each with its silky
pappus
Doubly
paripinnate leaves of Delonix regia
Aloe ferox in flower, bearing two
inflorescences on
peduncles
Stephania japonica is a vine with
peltate leaves.
Perfoliate leaves of
Smyrnium perfoliatum with stems passing through them
The leaves of
Aponogeton madagascariensis are
perforate.
The
perigonium of a moss (red in this case), also called a
splash-cup, surrounds the
antheridia and aids in dispersal of sperm.
Liquidambar styraciflua bud emerging from its protective brown
imbricate cataphyll scales, also known as
perules
Pelargonium lobatum
inflorescence, with showy petals projecting from inconspicuous protective
sepals
Petiolary glands on the petiole of a cherry leaf
Rock-splitting roots of the
petricolous large-leaved rock fig,
Ficus abutilifolia
The
phaneranthous habit of the red flowering gum,
Corymbia ficifolia, can attract pollinators such as the honey eater,
Anthochaera chrysoptera, from a considerable distance.
Seedlings of
Acacia fasciculifera bear leaves that illustrate the ancestral function of their
phyllodes as
petioles.
Pileus of the fruiting body of the fungus
Pluteus admirabilis
Glandular
pilose hairs on the stem of
Aquilegia grata
Bipinnate leaf anatomy showing a
pinna (or pinnule)
Simple
pinnate leaf of
Ekebergia capensis
Pistillate flowers of Shepherdia canadensis.
Compare
staminate flower.
Electron micrographs of sections of wood of a conifer (
Picea abies) show
pits in the tracheid walls.
Flowers in the
inflorescence of
Euphorbia platyphyllos open simultaneously, as a
pleiochasium.
The
corolla of
Datura discolor is
plicate.
Longitudinal section of maize kernel (scale=1.4 mm):
A=
pericarp, B=
aleurone, C=
stalk, D=
endosperm, E=
coleorhiza, F=
radicle, G=
hypocotyl, H=
plumule, I=
scutellum, J=
coleoptile
Pneumatophores on a species of
mangrove
The sharp projections on the trunk of the knobthorn,
Senegalia nigrescens, are
prickles rather than thorns, botanically speaking.
Procumbent growth habit of
Sagina procumbens, growing mainly along the soil surface, but without rooting
Carpobrotus and other
prostrate plants growing on sand in Sicily, striking root and binding the soil as they grow
Floral stages of the protandrous species:
Geranium incanum. The flower at first has intensely colored petals, and both
androecium and
gynoecium. After a day or so in bloom, it sheds the stamens and the color of the petals becomes somewhat paler.
Pubescent stem and
inflorescence of
Gomphrena celosioides
Punctate glands on
Artemisia nova are visible because they are not covered with epidermal
hairs.
Punctiform glands on the undersurface of a
Plectranthus leaf
Pyramidal growth
habit of
Picea pungens
Pyriform syconium ("fruit") of domestic fig
pachycaul
with a disproportionately thick trunk
pachycladous
with disproportionately thick stems
palate
An expanded lower lip of a flower that nearly or entirely blocks the opening of a flower tube, as in a
snapdragon flower.
palea
1. The upper of two
bracts enclosing a grass flower, major contributors to chaff in harvested grain.
2. Chaffy scales on the receptacles of many
Asteraceae.
3. Chaffy scales on the
stipe of many ferns.
paleate
Bearing
paleae or chaffy scales, as in description of the receptacle of a
capitulum of a plant in the
Asteraceae.
paleaceous
Chaff-like in texture.
palmate
1. leaf with
veins radiating out from a central point (usually at the top of a
petiole), resembling spread out fingers pointing away from the palm.
2. A
compound palmate leaf has
leaflets that radiate from a central point (usually at the top of a petiole).
palmatifid
Deeply divided into several lobes arising from more or less the same level.
palmatisect
Intermediate between
palmate and
palmatifid, i.e. the segments are not fully separated at the base; often more or less
digitate.
pandurate
shaped like the body of a
fiddle (mainly, of plant leaves)
panicle
A
compound raceme; an
indeterminate inflorescence in which the flowers are borne on branches of the main axis or on further branches of these.
papilionate
Butterfly-like; having a
corolla like that of a
pea.
papilla
A small, elongated protuberance on the surface of an organ, usually an extension of one
epidermal cell.
pappus
In daisy
florets, a tuft or ring of hairs or scales borne above the
ovary and outside the
corolla (representing the reduced
calyx); a tuft of hairs on a fruit.
paracarpel
Ill-defined term, variously interpreted and applied to: organs attached to
carpels;
staminodes close to the
gynoecium; and to a
pistillode in a
staminate flower
paraperigonium
An anomalous secondary outgrowth of the
perianthal meristem with
ramifying vasculature. See also
perigonium,
perianth, and
corona.
parasite
An organism living on or in a different organism, from which it derives nourishment. Some plant species are parasitic. Compare
saprophyte and
epiphyte.
parenchyma
A versatile ground tissue composed of living primary cells which performs a wide variety of structural and biochemical functions in plants.
parietal
Attached to the marginal walls of a structure, e.g. ovules attached to placentas on the wall of the ovary. See
placentation.
paripinnate
Having an even number of
leaflets (or
pinnae), i.e. terminated by a pair of pinnae as opposed to a single pinna. Compare
imparipinnate.
parthenocarpy
The development or production of
fruit without
fertilization. Compare
stenospermocarpy.
patent
Spreading; standing at 45–50° to the axis. See also
erecto-patent.
patulous
See
patent.
pauciflor
Having few flowers per
inflorescence. Compare
pluriflor and
uniflor.
pectinate
Pinnately divided with narrow segments closely set like the teeth of a comb.
pedate
Having a terminal lobe or
leaflet, and on either side of it an axis curving outward and backward, bearing lobes or leaflets on the outer side of the curve.
pedicel
The stalk of a
flower; may also be applied to the stalk of a
capitulum in the
Asteraceae.
peduncle
The stalk of an
inflorescence.
peltate
Shield-like, with the stalk attached to the lower surface and not to the
margin.
pellucid
Transmitting light; for example, said of tiny gland dots in the leaves of e.g.
Myrtaceae and
Rutaceae that are visible when held in front of a light.
pendulous
Hanging, for example an ovule attached to a placenta on the top of the ovary. Compare
suspended.
penicillate
Tufted like an artist's brush; with long hairs toward one end.
penninervation
With
pinnately arranged
veins.
pentamerous
In five parts, particularly with respect to flowers, five parts in each whorl. See also
trimerous and
tetramerous.
pepo
A type of
berry formed from an
inferior ovary and containing many seeds, usually large with a tough outer skin (e.g. a
cucumber,
pumpkin or
watermelon.)
perennating
Of an organ that survives vegetatively from season to season. A period of reduced activity between seasons is usual.
perennial
A plant whose life span extends over several years.
perfect
(of a
flower)
Bisexual; containing both male and female reproductive parts in the same
inflorescence. Contrast
imperfect.
perfoliate
With its base wrapped around the stem (so that the stem appears to pass through it), e.g. of leaves and
bracts.
perforate
With many holes. Used to describe the texture of pollen exine, and also to indicate that
tracheary elements have a perforation plate. See also
fenestrate.
perforation plate
in a
tracheary element, part of the cell wall that is perforated; present in vessel members but not in tracheids. Should not be confused with a
pit.
perianth
The collective term for the
calyx and
corolla of a
flower (generally used when the two are too similar to be easily distinguishable). Abbreviation: P; for instance, P 3+3 indicates the calyx and corolla each have 3 elements, i.e. 3
sepals + 3
petals.
pericarp
The wall of a fruit, developed from the
ovary wall.
periclinal
Curved along parallel to a surface. Compare
anticlinal.
pericycle
A cylinder of parenchyma or sclerenchyma cells that lies just inside the endodermis and is the outer most part of the stele of plants.
perigonium
In
flowering plants,
synonym of
perianth.
2. In
mosses, the leaves surrounding the antheridia, also called a
splash-cup, e.g. in
Polytrichum juniperinum.
perigynium
A sac from a modified tubular bract, or when fully closed an
utricle, around the
pistillate flower of
sedges
perigynous
Borne around the ovary, i.e. of perianth segments and stamens arising from a cup-like or tubular extension of receptacle (free from the ovary but extending above its base). Compare
epigynous and
hypogynous.
persistent
Remaining attached to the plant beyond the usual time of falling, for instance sepals not falling after flowering, flower parts remaining through maturity of fruit. Compare
deciduous and
caducous.
perule
1. The scales covering a leaf or
flower bud, or a reduced scale-like leaf surrounding the bud. Buds lacking perulae are referred to as "naked".
2. In Camellias the final
bracts and sepals become indistinguishable and are called perules.
3. A kind of sac formed by the adherent bases of the two lateral
sepals in certain orchids.
petal
In a
flower, one of the segments or divisions of the inner whorl of non-fertile parts surrounding the fertile organs, usually soft and conspicuously colored. Compare
sepal,
tepal.
petalody
The transformation of reproductive organs of flower into
petals.
petaloid
Like a
petal; soft in texture and colored conspicuously.
petiolary (or petiolar)
Associated with a
petiole, as in petiolary glands.
petiolate
(of a
leaf) Having a
petiole. Contrast
sessile.
petiole
The stalk of a
leaf.
petiolule
The stalk of a
leaflet.
petricolous
Rock-dwelling; living on or among rocks.
phaneranthous
Showy, as in showy flowers that advertise to
pollinators, as opposed to
aphananthous (unshowy)
phanerogam
Gymnosperms and angiosperms; plants producing stamens and gynoecia; literally plants with conspicuous sexual reproductive organs. Compare
cryptogams.
phenology
The study of the timing of seasonal biological phenomena, such as flowering, leaf emergence, fruit ripening and leaf fall.
phloem
Specialized conducting tissue in
vascular plants that transports
sucrose from the leaves to other plant organs.
photosynthesis
Process by which energy from sunlight is used to convert
carbon dioxide and
water into
simple sugars in cells containing
chloroplasts. All plants, except certain
parasites, can perform photosynthesis.
phyllary
Individual
bract within an
involucre or
involucel.
phyllid
Leaf-like extension of the stem in
Bryophytes
phyllode
A leaf with the blade much reduced or absent, and in which the petiole and or
rachis perform the functions of the whole leaf, e.g. many
acacias. Compare
cladode.
phyllopodium
(in ferns) A short outgrowth of the stem on which the
frond is borne and which remains attached to the
rhizome after the frond has been shed.
phylloplane
the surface of a leaf, considered as a habitat for organisms.
phyllosphere
The above-ground surface of plants as a habitat for
epiphytic microorganisms.
phylum
A level of
classification or taxonomic rank below
kingdom and above
class. Traditionally, in botany the term
division has been used instead of phylum.
phytomelan
A black, inert, organic material that forms a crust-like covering of some seeds, commonly found in
Asparagales,
Asteraceae, etc.
pileate
Having a cap, a
pileus.
pileus
A cap or cap-shaped structure, such as the cap of mushrooms or the
plumule of some
monocotyledons.
piliform
Having the shape of a cap, a
pileus.
pilose
covered with soft, weak, thin and clearly separated hairs, which are usually defined as long and sometimes ascending.
pinna
A primary segment of a
compound leaf.
pinnate
A
compound leaf with
leaflets arranged on each side of a common petiole or
axis; also applied to how the lateral
veins are arranged in relation to the main vein.
pinnatifid
Pinnately lobed.
pinnatisect
pinnately divided almost to midrib but segments still confluent.
pinnule or pinnula
Usage varies:
ultimate free division (or
leaflets) of a
compound leaf,
or
a pinnate subdivision of a multipinnate leaf.
pistil
1. a single
carpel when the carpels are free.
2. a group of carpels when the carpels are united by the fusion of their walls.
pistillate flower
a flower containing one or more
pistils but no fertile
stamens. Sometimes called a female flower. Contrast with
staminate flower
pistillode
A sterile or rudimentary pistil such as may appear in a
staminate flower.
pit
In
tracheary elements, a section of the cell wall where the secondary wall is missing, and the primary wall is present. Pits generally occur in pairs and link two cells.
pith
The central region of a stem, inside the
vascular cylinder; the spongy
parenchymatous central tissue in some stems and roots.
placenta
The tissue within an ovary to which the ovules are attached.
placentation
The arrangement of ovules inside ovary; for example axile, free-central, parietal, marginal, basal, or apical.
Plant Breeders Rights (PBR)
These rights, governed by Plant Breeder's Rights Acts give the plant breeder legal protection over the propagation of a cultivar, and the exclusive rights to produce and to sell it, including the right to license others to produce and sell plants and reproductive material of a registered, deliberately bred variety. Compare UPOV.
Plant Variety Rights (PVR)
Governed by the Plant Variety Rights the registration of new varieties is now governed by Plant Breeders Rights.
The time between successive leaf initiation events.
pleiochasium
pl. pleiochasia. An inflorescence in which several buds come out at the same time. Compare
monochasium and
dichasium.
plicate
Pleated; folded back and forth longitudinally like a fan, such as the leaves of
fan palm species. The concept often appears in specific names in forms such as
Kumara plicatilis and
Acacia plicata. Commonly such names are not correctly appropriate, but are applied to
distichous structures rather than plicate.
-plinerved
(of leaves) A suffix indicating that the main nerves are lateral and arise from a point distinctly above the base of the leaf. Combined with a numerical prefix to form words like 3-plinerved, 5-plinerved, and so on. Such leaves are especially characteristic of the family Melastomataceae. See for example
Dissotis.
plumose
Like a feather; with fine hairs branching from a main axis.
plumule
The part of an embryo that gives rise to the shoot system of a plant. Compare
radicle.
pluriflor
Having many flowers per
inflorescence. See also
pauciflor and
uniflor.
pluriovulate
Having many
ovules as in
placentae,
carpels, or
ovaries.
A vertical appendage, aerial at low tide, on the roots of some plants. Pneumatophore functions are unclear, but possibly related to gas exchange, or to root anchoring. Pneumatophores typically occur on
mangrove roots, but some
versions occur on species of conifers, such as some in the
Taxodioideae.
pod
1. A
legume, the fruit of a leguminous plant, a dry fruit of a single
carpel, splitting along two
sutures.
2. A
siliqua and
silicula, the fruit of
Brassicaceae, a dry fruit composed of two
carpels separated by a partition.
podocarpium
In four
genera of the coniferous family
Podocarpaceae (
Acmopyle,
Dacrycarpus,
Falcatifolium, and
Podocarpus), a group of fleshy fused
bracts beneath the female
cone, often brightly-colored, which swell to enclose the developing seeds above and attract fruit-eating animals.
pollen
powdery mass shed from anthers (of angiosperms) or microsporangia (of gymnosperms); the microspores of seed plants; pollen-grains.
pollen-mass
pollen-grains cohering by a waxy texture or fine threads into a single body;
pollinium, e.g. in
orchids.
pollen transmitting tissue
the tissue in the
style of a flower through which the
pollen tubes grow.
pollination
The transfer of
pollen from a male organ (such as an
anther) to the receptive region of a female organ (such as a
stigma).
pollinium
See
pollen-mass.
polygamodioecious
Having bisexual and male flowers on some plants and bisexual and female flowers on others. Compare
androdioecious,
andromonoecious,
dioecious,
monoecious,
polygamomonoecious, and
polygamous.
polygamomonoecious
having male, female, and bisexual flowers on the same plant. Compare
androdioecious,
andromonoecious,
polygamodioecious, and
polygamous.
polygamous
having
bisexual and
unisexual flowers on the same plant.
polymorphic
Of several different kinds (in respect to shape and/or size), hence
polymorphism. See also
monomorphic (a single type) and
dimorphic (two types)
polyphyllous
having many leaves or
perianth segments. Compare
symphyllous,
gamophyllous, and
apophyllous.
polyploid
with more than two of the basic sets of
chromosomes in the
nucleus; any
sporophyte with cells containing three or more complete sets of chromosomes. Various combinations of words or numbers with '-ploid' indicate the number of
haploid sets of chromosomes, e.g. triploid = 3 sets,
tetraploid = 4 sets, pentaploid = 5 sets, hexaploid = 6 sets, and so on.
polystemonous
having
numerous stamens; the number of stamens being at least twice the number of sepals or petals, but not strictly three or four times that number.
pome
A
fruit that has developed partly from the
ovary wall but mostly from the
hypanthium (e.g. an
apple).
population
1. All individuals of one or more species within a prescribed area.
2. A group of organisms of one species, occupying a defined area and usually isolated to some degree from other similar groups.
3. In statistics, the whole group of items or individuals under investigation.
poricidal
Opening by
pores, as with the
capsule of a poppy or the
anthers in several families of plants. Compare
longicidal.
posterior
Positioned behind or toward the rear. Contrast
anterior.
prickle
A hard, pointed outgrowth from the surface of a plant (involving several layers of cells but not containing a
vein); a sharp outgrowth from the bark, detachable without tearing wood. Compare
thorn.
primary vein
The single
vein or array of veins that is conspicuously larger than any others in a leaf. In
pinnate venation, the single primary vein can generally be found in the middle of the leaf; in
palmate venation, several such veins radiate from a point at or near the base of the leaf.
procumbent
Spreading along the ground but not rooting at the
nodes; not as close to the ground as
prostrate.
propagule
Any structure capable of generating a new plant; includes
seeds,
spores,
bulbils, etc.
pro parte
In part. In nomenclature, used to denote that the preceding taxon includes more than one currently recognized entity, and that only one of those entities is being considered.
prophyll
A leaf formed at the base of a
shoot, usually smaller than those formed later.
prostrate
Lying flat on the ground; commonly rooting at nodes that touch the soil surface.
protandrous
Having male sex organs which mature before the female ones, e.g. a flower shedding pollen before the stigma is receptive. Compare
protogynous.
proteranthous
With new
leaves appearing before
flowers. See also
hysteranthous and
synanthous.
prothallus
A
gametophyte plant, usually flattened and delicate, e.g. in ferns and fern allies.
protogynous
Having female sex organs which mature before the male ones, e.g. a flower shedding
pollen after the
stigma has ceased to be receptive. Compare
protandrous.
proximal
Near the point of origin or attachment. Compare
distal.
pruinose
Covered with a powdery, waxy material; having a
bloom.
pseudanthium
A type of
inflorescence occurring in the
Asteraceae and
Euphorbiaceae, in which multiple flowers are grouped together to form a flower-like structure, commonly called a
head or
capitulum.
pseudo-
A prefix meaning "false, not genuine", e.g. a pseudo-bulb is a thickened, bulb-like internode in
orchids, but not an actual
bulb.
pseudobasifixed
(of an
anther) Connected to the
filament of the
stamen by connective tissue which extends in a tube around the filament tip. See also
basifixed and
dorsifixed.
pseudostipule
An enlarged, persistent
axillary bud scale that resembles a
stipule; common in
Bignoniaceae.
pseudoverticillate
Having the appearance of being whorled (
verticillate), without actually being so.
puberulous
Covered with minute soft erect hairs.
pubescent
Downy; covered with short, soft hairs, especially erect hairs.
pulverulent
Having powdery or crumbly particles as if pulverized.
pulvinate
Having a
pulvinus.
pulvinus
a swelling at either end of a
petiole of a leaf or
petiolule of a leaflet, e.g. in
Fabaceae, that permits leaf movement.
punctate
(from Latin puncta= puncture or prick-mark) marked with an indefinite number of dots, or with similarly small items such as translucent glands or tiny hollows.
punctiform
Dot-like or in the shape of a prick-mark.
pungent
Having a sharp, hard point.
pustule
A blister-like swelling.
pustulate
Having
pustules.
pyramidal
(of a growth habit) Conical or pyramid-shaped. Most familiar in some coniferous trees, especially species adapted to snowy climates
pyrene
The stone of a
drupe, consisting of the seed surrounded by the hardened
endocarp.
pyriform
Pear-shaped; a term for solid shapes that are roughly conical in shape, broadest one end and narrowest at the other. As a rule the
distal third of their length is the broadest, and they are narrowest near the
proximal end, the base, where the stalk, if any, attaches.
pyrophile
Plants which need fire for their reproduction.
pyrophyte
Plants which have adapted to tolerate fire.
Q
Siliques of
Conringia orientalis tend toward a
quadrate cross section.
quadrate
More or less
square.
R
Bulbinella latifolia
racemes. The flowers are already open at the bottom; at the top, the axis is still growing and budding.
Rachis of
Vachellia karroo bipinnate leaf, with components labelled as follows: A. Rachilla (the diminutive of rachis)
B. Pinnule
C. Jugary glands
D. Juga (plural of
jugum)
E. Base of petiole
F. Petiolary gland
G. Rachis
Radicles emerging from germinating seeds
Reniform kidney bean seeds
A leaf of
Ficus carica, illustrating
reticulate venation
The central leaflets of the
ternate leaves of
Searsia glauca are
oblate and commonly
retuse.
Typical
rhizome. This one is a specimen of
Iris pseudacorus.
Grafting kiwifruit vine
scion onto
rootstock below
Unidentified
Gasteria bearing leaves with a
rugose surface, banded with
callosities
Rugose leaves of
Alocasia are stiffer than flat leaves of the same size and thickness would be.
Unidentified
Crassula bearing
rugulose leaves with fine wrinkles in the epidermis
The
runcinate lobes of a
Taraxacum officinale leaf point downward, i.e. toward the stem.
raceme
An
indeterminate inflorescence in which the main axis produces a series of flowers on lateral stalks, the oldest at the base and the youngest at the top. Compare
spike. Also racemiform or racemoid - having the form of a raceme.
rachilla (rhachilla)
1. the axis of a grass
spikelet, above the
glumes; see
spikelet.
2. the
rachis of higher order in leaves that are compound more than once
rachis
The axis of an inflorescence or a
pinnate leaf; for example ferns; secondary
rachis is the axis of a
pinna in a bipinnate leaf distal to and including the lowermost
pedicel attachment.
radial
With structures radiating from a central point as
spokes on a wheel (e.g. the lateral spines of a
cactus).
radiate
(of daisies, of a capitulum) With
ray floret surrounding disc florets.
radical
Springing from the root; clustered at base of stem.
radicle
The part of an
embryo giving rise to the root system of a plant. Compare
plumule.
rainforest
A moist temperate or tropical forest dominated by broad-leaved trees that form a continuous canopy.
ramet
An individual member of a
clone.
ramicaul
a single-leafed stem, as in
Pleurothallis orchids.
ramify
To divide or spread out into individual branches or branchlike parts.
ray
1. zygomorphic (ligulate)
flowers in a
radiate flowerhead, that is, ray-florets/flowers, for example
Asteraceae.
2. each of the branches of an
umbel.
receptacle
the
axis of a
flower, in other words,
floral axis;
torus; for example in
Asteraceae, the floral base or
receptacle is the expanded tip of the peduncle on which the flowers are
inserted.
recumbent
bent back toward or below the horizontal.
recurved
bent or curved backward or downward.
reduplicate
folded outward, or with the two
abaxial surfaces together.
reflexed
bent sharply back or down.
registered name
a
cultivar name accepted by the relevant
International Cultivar Registration Authority.
registration
1. the act of recording a new
cultivar name with an
International Cultivar Registration Authority.
2. recording a new cultivar name with a statutory authority like the
Plant Breeder's Rights Office.
3. recording a
trademark with a trade marks office.
regular
See
actinomorphic.
reniform
Kidney-shaped.
replum
a framework-like
placenta to which the seeds attach, and which remains after each
valve drops away.
resupinate
Describing leaves or flowers that are in an inverted position because the
petiole or
pedicel, respectively, is twisted 180 degrees. compare:
hyper-resupinate.
reticulate
forming a network (or reticulum), e.g.
veins that join one another at more than one point.
retrorse
Bent backward or downward. Compare
antrorse.
retuse
Having a blunt (
obtuse) and slightly notched apex.
revision
an account of a particular plant group, like an abbreviated or simplified
monograph. Sometimes confined to the plants of a particular region. Similar to a monograph in clearly distinguishing the taxa and providing a means for their identification. Compare
monograph.
revolute
rolled under (downward or backward), for example when the edges of leaves are rolled under toward the midrib. Compare
involute.
rhachis
See
rachis.
rhizodermis
the root
epidermis, the outermost primary cell layer of the root
rhizome
a perennial underground stem usually growing horizontally. See also
stolon. Abbreviation: rhiz.
rhizomatous
(adj.) having above-ground stems that are derived from below-ground stems (rhizomes). Compare arhizomatous (arhizomatic).
rhizosphere
the below-ground surface of plants and adjacent soil as a habitat for microorganisms.
rhytidome
the dead region of the bark and root that lies outside the periderm.
rhombic
like a
rhombus: an oblique figure with four equal sides. Compare
trapeziform and
trullate.
rhomboid
a four-sided figure with opposite sides parallel but with adjacent sides an unequal length (like an oblique rectangle); see also
rhombic.
rhomboidal
a shape, for instance of a leaf, that is roughly diamond-shaped with length equal to width.
rimose
with many cracks, as in the surface of a
crustose areolate lichen.
root
a unit of a plant's axial system which is usually underground, does not bear leaves, tends to grow downward, and is typically derived from the
radicle of the
embryo.
root hairs
outgrowths of the outermost layer of cells just behind the root tips, functioning as water-absorbing organs.
root microbiome
the dynamic community of microorganisms associated with plant roots.
1. the part of a budded or
grafted plant which supplies the root system, also simply called a stock.
2. plants selected to produce a root system with some specific attribute, e.g. a virus-free rootstock.
rosette
when parts are not whorled or opposite but appear so, due to the contractions of
internodes, e.g. the petals in a double rose or a basal cluster of leaves (usually close to the ground) in some plants.
rostellate
possessing a beak (rostellum). Synonym of
rostrate.
rostrate
with a beak.
rotate
circular and flattened; for example a
corolla with a very short tube and spreading lobes (for instance some
Solanaceae).
ruderal
a plant that colonises or occupies disturbed waste ground. See also
weed.
rudiment
In the structure of a plant, an item that is at best hardly functional, either because it is immature and has not yet completed its development (such as a leaf still incompletely formed inside a bud), or because its role in the organism's morphology cannot be completed and therefore is futile (such as the leaf rudiment at the tip of a phyllode, that will be shed while immature, because the leaf function will be taken over by the phyllode). Compare
cataphyll and
vestige.
rudimentary
Being of the nature of a
rudiment; at most barely functional because incompletely developed; begun, but far from completed, either temporarily or permanently. Compare
vestigial.
rugose
Wrinkled, either covered with wrinkles, or crumpled like a wrinkled leaf, either as a stiffening structure, or in response to disease or insect damage.
rugulose
Finely wrinkled.
ruminate
(usually applied to
endosperm) Irregularly grooved or ridged; appearing chewed, e.g. the endosperm in certain members of
Myristicaceae.
runcinate
Sharply
pinnatifid or cleft, with the segments directed downward.
runner
See
stolon.
rupicolous
Rupestral,
saxicolous, growing on or among rocks. Compare
epilithic and
lithophytic.
rush
A plant of the family
Juncaceae or, more loosely, applied to various
monocotyledons.
S
Sagittate leaves of an
Alocasia plant
Salverform flowers of
Plumbago auriculata
Trametes versicolor, the turkey tail fungus, is a
saprotroph that consumes dead wood in forests. Its common name comes from the conspicuously patterned brackets, but the main body of the saprotroph consists of the largely invisible
mycelium that penetrates the dead wood and digests it.
Strawberry plants reproduce mainly by
sarments,
stolons such as these, often called
runners; at their nodes the sarments put up tufts of leaves and strike root if there is any good soil beneath.
Micrograph of the
scabrid undersurface of the leaf of
Stipa pulcherrima.
Amaryllis belladonna in flower, an example of a leafless scape emerging directly from the underground bulb before the seasonal leaves
Involucral bracts of
Syncarpha species are as
scarious as tissue paper, but look like live petals for years, so they are known as "Everlastings" and valued for dried arrangements.
Isolated
sclereid or stone cell in plant tissue
Sclereids in gritty particles of pear tissue
Sepals on
Geranium thunbergii, five separated behind the
petals of an open flower, and a connected set enclosing an unopened bud
Sericeous leaves of
Podalyria sericea, the silver sweet pea bush
The fruits of
Lepidium bonariense are
silicles, green and circular, with a notch at the apex.
Silky foliage of the silvertree,
Leucadendron argenteum
Sori under the leaf of the fern
Rumohra adiantiformis. Some are still covered by their
indusia.
Spadix of
Amorphophallus maximus within its
spathe. The female flowers are around the bottom of the spadix, the male flowers above, and the sterile top part is the major source of pollinator attractants.
The
convolute spathe around the spadix of
Zantedeschia aethiopica
Drosera spatulata leaves are markedly
spathulate.
The flowering
spike of this
Salvia nemorosa differs from a
raceme in that the flowers are practically
sessile.
Spines emerging from the
areoles of an
Echinopsis species
Spinescent leaves of
Salsola australis: stiff, narrowed, and with lobes ending in spiny points
Bird nest fungi,
Nidulariaceae, bear examples of
splash-cups with spores that are spread by raindrops.
Sporangia of the fungus
Rhizopus
Staminate flowers of Shepherdia canadensis
Manilkara hexandra flowers have both
stamens with
anthers and
staminodes that have no anthers.
Subulate leaves are narrow with an elongated, tapering tip, as seen on this species of
Aloe.
The large,
succulent,
acaulescent,
linear,
cuspidate mottled leaves of a
Gasteria species and the small, succulent,
cordate leaves of a
Crassula species contrast with the
linear,
herbaceous leaves of a
Hypoxis species.
Suckers around the trunk of
Dypsis lutescens
Sulcate (specifically polysulcate) grooves along the stem of
Scorzonera cana
Superior ovary ovary in an
Aloe species. One flower is sectioned to display the
pistil and
hypanthium.
The
suture along the concave curve of the pod of a
Crotalaria incana, along which the seeds are attached, is where the single carpel has folded shut.
An undamaged
syconium of a
Ficus species, plus two more cut open longitudinally to display the fruit within
saccate
Pouched or shaped like a sack.
sagittate
Shaped like the head of an arrow; narrow and pointed but gradually enlarged at the base into two straight lobes directed downward; may refer only to the base of a leaf with such lobes. Compare
hastate.
salverform
Shaped like a salver - Trumpet-shaped; having a long, slender tube and a flat, abruptly expanded limb
samara
A dry,
indehiscent fruit with its wall expanded into a wing, e.g. in the genus
Acer.
samphire
A common name given to various edible coastal plants, such as
Salicornia spp. (
Amaranthaceae),
Crithmum maritimum (
Apiaceae) and
Limbarda crithmoides (
Asteraceae).
sanguine
(from Latin sanguineus) Blood-colored: crimson; the color of blood.
saprophyte
A plant, or loosely speaking, a fungus or similar organism, deriving its nourishment from decaying organic matter such as dead wood or humus, and usually lacking
chlorophyll. Compare
parasite,
saprotroph, and
epiphyte.
saprotroph
An organism deriving its nourishment from decaying organic matter. Contrast
parasite and
epiphyte.
sarment
A long, slender,
prostrate stolon, commonly called a
runner.
sarmentose
Reproducing by
sarments; strawberry plants are the most familiar example.
saxicolous
Growing on stone, like some
lichens.
scabrid .
Rough to the touch, with short hard protrusions or hairs.
scalariform
Ladder-like in structure or appearance.
scale
1. A reduced or rudimentary leaf, for example around a dormant bud.
2. A flattened epidermal outgrowth, such as those commonly found on the leaves and rhizomes of ferns.
scandent
Climbing, by whatever means. See also:
scandent in Wiktionary.
scape
Usages vary, e.g.: a leafless
peduncle arising directly from the ground, or a
stem-like flowering stalk of a plant with
radical leaves.
scapose
Having the floral axis more or less
erect with few or no
leaves; consisting of a
scape.
scarious
Dry and
membranous.
schizocarp
A dry
fruit formed from more than one
carpel but breaking apart into individual carpels (
mericarp) when
ripe. For illustration, see
mericarp
scion
The
aerial part of a
graft combination, induced by various means to unite with a compatible understock or
rootstock.
sclereid
A cell with a thick,
lignified,
cell wall that is shorter than a
fiber cell and dies soon after the thickening of its cell wall.
sclerenchyma
A strengthening or supporting tissue composed of
sclereids or of a mixture of sclereids and fibers.
sclerophyll
A plant with hard, stiff leaves; any structure stiffened with thick-walled cells.
scorpioid
(of a
cymose inflorescence) Branching alternately on one side and then the other. Compare
helicoid.
scrobiculate
Having very small pits.
scrubland
Dense vegetation dominated by
shruba.
scurf
Minute, loose, membranous
scales on the surface of some plant parts, such as leaves.
secondary metabolite
Chemicals produced by a plant that do not have a role in so-called primary functions such as growth, development, photosynthesis, reproduction, etc.
secretory tissue
The tissues concerned with the secretion of gums, resins, oils and other substances in plants.
section (sectio)
The category of supplementary taxa intermediate in rank between subgenus and series. It is a singular noun always written with a capital initial letter, in combination with the generic name.
secund
Having all the parts grouped on one side or turned to one side (applied especially to inflorescences).
sedge
A plant of the family
Cyperaceae.
seed
A ripened
ovule, consisting of a protective coat enclosing an embryo and food reserves; a propagating organ formed in the sexual reproductive cycle of
gymnosperms and
angiosperms (together, the
seed plants).
segment
A part or subdivision of an organ, e.g. a petal is a segment of the corolla. A term sometimes used when the sepals and petals are indistinguishable.
self-pollination
(also selfing) The acceptance by stigmas of pollen from the same flower or from flowers on the same plant, which means they are self-compatible.
semaphyll
A structure such as a
bract or
sepal (if the remainder of the
perianth is inconspicuous) which has become modified to attract
pollinators.
semelparity
When a plant flowers once then dies.
semiterete
Rounded on one side but flat on the other. See also
terete.
senecioid
See
anthemoid.
sensitive
A descriptive term for stigmas that, in response to touch, close the two lobes of the stigma together, ending the receptivity of the stigma, at least for the time that the lobes are closed together.
Mimulus is perhaps the best-known example.
sensu
In the sense of.
sensu auct.
(of a plant group or name) As cited by a named authority.
sensu amplo
(of a plant group or name) In a generous or ample sense.
sensu lato
(of a plant group) In a broad sense.
sensu strictissimo
(of a plant group) In the narrowest sense.
sensu stricto
(of a plant group) In a narrow sense.
sepal
In a flower, one of the segments or divisions of the outer
whorl of non-fertile parts surrounding the fertile organs; usually green. Compare
petal,
tepal.
septicidal
(of a fruit)
Dehiscing along the partitions between
loculi. Compare
loculicidal.
septum
A partition, e.g. the
membranous wall separating the two valves of the pod of
Brassicaceae.
seriate
Arranged in rows.
sericeous
Silky with dense
appressed hairs.
series
The category of supplementary taxa intermediate in rank between
section and
species. It is often used as a plural adjective, as in "
Primula subgenus Primula sect. Primula series Acaules".
serrate
Toothed with asymmetrical teeth pointing forward; like the cutting edge of a saw.
serrulate
Finely
serrate.
sessile
Attached without a stalk, e.g. of a leaf without a
petiole or a
stigma, when the
style is absent.
seta
A bristle or stiff hair (in
Bryophytes, the stalk of the
sporophyte). A terminal seta is an
appendage to the tip of an organ, e.g. the primary
rachis of a
bipinnate leaf in
Acacia.
sheath
A tubular or rolled part of an organ, e.g. the lower part of the leaf in most
grasses.
sheathing
When the rolled or tubular part of a plant contains another it is described as sheathing.
shoot
The
aerial part of a plant; a
stem and all of its dependent parts (leaves, flowers, etc.).
shrub
A
woody perennial plant without a single main
trunk, branching freely, and generally smaller than a
tree.
sigmoid
Shaped like the letter 'S'.
silicula or silicle
A fruit like a
siliqua, but stouter, not more than twice as long as wide.
silique
siliqua
A dry, dehiscent fruit (in contrast to a
silicula, more than twice as long as wide) formed from a
superior ovary of two
carpels, with two
parietal placentas and divided into two
loculi by a 'false' septum.
silky
Densely covered with fine, soft, straight,
appressed hairs, with a lustrous sheen and satiny to the touch.
silviculture
The science of
forestry and the cultivation of
woodlands for commercial purposes and wildlife conservation.
simple
Undivided or unsegmented, e.g. a leaf not divided into
leaflets (note, however, that a simple leaf may still be
entire,
toothed or
lobed) or an unbranched hair or inflorescence.
sinuate
Having deep, wave-like depressions along the
margins, but more or less flat. Compare
undulate.
sinus
A notch or depression between two lobes or teeth in the
margin of an organ.
solitary
Single, of flowers that grow one plant per year, one in each axil, or widely separated on the plant; not grouped in an inflorescence.
sorus
A cluster of
sporangia. Sori typically occur in ferns, some
Algae and some fungi. In many fern species the sorus is covered by a protective
indusium.
sp.
An abbreviation of
species (singular), often used when the
genus is known but the species has not been determined, as in "
Brassica sp." See
spp..
spp.
An abbreviation of
species (plural), often used to collectively refer to more than one species of the same
genus, as in "
Astragalus spp." See
sp..
spadix
A
spicate (spike-like)
inflorescence with the flowers crowded densely, even solidly, around a stout, often
succulent axis. Particularly typical of the family
Araceae
spathe
A large
bract ensheathing an inflorescence. Traditionally any broad, flat blade.
spathulate or spatulate
Spoon-shaped; broad at the tip with a narrowed projection extending to the base.
species
A group, or populations of individuals, sharing common features and/or ancestry, generally the smallest group that can be readily and consistently recognized; often, a group of individuals capable of interbreeding and producing fertile offspring. The basic unit of classification, the category of taxa of the lowest principal rank in the nomenclatural hierarchy. Strict assignment to a species is not always possible, as it is subject to particular contexts, and the
species concept under consideration.
specific epithet
Follows the name of the genus, and is the second word of a botanical binomial. The generic name and specific epithet together constitute the name of a species, i.e. the specific epithet is not the species name.
speirochoric
Unintentional introduction by seeds.
Compare
agochoric.
spica
Another name for a
spike.
spike
An unbranched,
indeterminate inflorescence in which the flowers are without stalks. Compare
raceme.
spikelet
A subunit of a
spike inflorescence, especially in
grasses,
sedges, and some other
monocotyledons, consisting of one to many flowers and associated
bracts or
glumes.
spine
A stiff, sharp structure formed by the modification of a plant organ that contains vascular tissue, e.g. a lateral branch or a
stipule; includes thorns.
spinescent
Ending in a spine; modified to form a spine.
spiral
Of arrangement, when plant parts are arranged in a succession of curves like the thread of a screw, or coiled in a cylindrical or conical manner.
splash-cup (sporangia)
A cup-like structure in fungi such as
Nidulariaceae and in
cryptogams such as some mosses. The cups function in spore dispersal, in which the energy of raindrops falling into the cup causes the water to splash outward carrying the spores.
sporangium (sporangia)
A structure in which spores are formed and from which the mature spores are released
sporangiophore
An organ bearing sporangia, e.g. the cones of
Equisetum.
spore
A
haploid propagule, produced by
meiosis in diploid cells of a
sporophyte that can germinate to produce a multicellular
gametophyte.
sporocarp
A fruiting body containing
spores.
sporophyll
In
pteridophytes, a modified leaf that bears a
sporangium or sporangia.
sporophyte
The
diploid multicellular phase in the
alternation of generations of plants and algae that produces the spores. Compare
gametophyte.
sport
A naturally occurring variant of a species, not usually present in a population or group of plants; a plant that has spontaneously mutated so that it differs from its parent plant.
spreading
Extending horizontally, e.g. in branches. Standing out at right angles to an axis, e.g. in leaves or hairs.
spur
1. a short shoot.
2. a conical or tubular outgrowth from the base of a
perianth segment, often containing nectar.
squamule
Small scales.
squamulose
Covered with small scales (
squamules).
squarrose
Having tips of leaves, stems, etc. radiating or projecting outward, e.g. in the moss
Rhytidiadelphus squarrosus.
s.t.
An abbreviation for "sometimes". Compare
usu. and
oft..
stalk
The supporting structure of an organ, usually narrower in diameter than the organ itself.
stamen
The male organ of a flower, consisting (usually) of a stalk called the
filament and a pollen-bearing head called the
anther.
staminate flower
A flower with
stamens but no
pistil.
staminode
A sterile
stamen, often
rudimentary, sometimes
petal-like. Commonly has a function in attracting pollinators that feed on the staminodes.
staminophore
A structure, around the apex of eucalypt, myrtaceae hypanthia, that supports the stamens.
standard
The large posterior petal of pea-flowers.
standard specimen
A representative specimen of a
cultivar or other taxon which demonstrates how the name of that taxon should be used.
stele
The primary vascular system (including
phloem,
xylem, and
ground tissue) of plant stems and roots.
stellate
Star-shaped.
stem
The plant
axis, either aerial or subterranean, which bears nodes, leaves, branches, and flowers.
stem-clasping
See
amplexicaul.
stenospermocarpy
The development or production of fruit that is seedless or has minute seeds because of the abortion of seed development. Compare
parthenocarpy.
sterile
Infertile, as with a
stamen that does not bear pollen or a flower that does not bear seed.
stigma
The pollen-receptive surface of a
carpel or group of fused carpels, usually sticky; usually a point or small head at the summit of the
style.
stipe
Generally a small stalk or stalk-like structure. The
stalk of a
frond of a fern; the stalk supporting the
pileus of a mushroom; the stalk of a seaweed such as a
kelp; the stalk-like support of a
gynaecium or a carpel
stipella
One of two small secondary
stipules at the base of
leaflets in some species.
stipitate
stalked; borne on a
stipe; of an
ovary, borne on a
gynophore.
stipulate
Bearing
stipules.
stipule
A small appendage at the bases of leaves in many
dicotyledons.
See
rootstock.
stolon
A slender,
prostrate or trailing stem, producing roots and sometimes erect shoots at its
nodes. See also
rhizome.
stoloniferous
Having
stolons.
stoma
A pore or small hole in the surface of a leaf (or other aerial organ) allowing the exchange of gases between tissues and the atmosphere.
stone cell
a
sclereid cell, such as the cells that form the tissue of nut shells and the stones of
drupes.
striate
Striped with parallel, longitudinal lines or ridges.
strigillose
Minutely strigose.
strigose
Covered with
appressed, straight, rigid, bristle-like hairs; the appressed equivalent of
hispid.
strobilus
A cone-like structure consisting of
sporophylls (e.g.
conifers and
club mosses) or
sporangiophores (e.g. in
Equisetopsida) borne close together on an
axis.
style
An elongated part of a
carpel or a group of fused carpels between the
ovary and the
stigma.
stylodium
An elongate
stigma that resembles a
style; a false style, e.g. commonly found in the
Poaceae and
Asteraceae.
stylopodium
A swelling on top of the ovary, at the base of the
styles commonly found in flowers of the
Apiaceae.
stylulus
The elongated apex of a free
carpel which functions like the style of a
syncarpous ovary, allowing
pollen tubes from its
stigma to enter the
locule of only that carpel.
subacute
Having a tapered but not sharply pointed form; moderately acute. See also
acute.
subcoriaceous
Slightly leathery or
coriaceous.
subgenus
A category of supplementary taxa intermediate between
genus and
section. The name of a subgenus is a singular noun, always has a capital initial letter and is used in combination with the generic name, e.g.
Primula subgenus Primula.
subglobose
Inflated, but less than spherical. See also
globose.
suborbicular
Nearly orbicular, flat and almost circular in outline. See also
orbicular.
subpetiolate
(of a
leaf) Having an extremely short
petiole, and may appear
sessile.
subquadrangular
Not quite square. Compare
quadrangular.
subshrub
A small
shrub which may have partially
herbaceous stems, but generally a woody plant less than 1 metre (3.3 ft) high.
subspecies
A taxonomic category within a
species, usually used for geographically isolated or morphologically distinct populations of the same species. Its taxonomic rank occurs between species and
variety.
subtend
To stand beneath or close to, as in a
bract at the base of a flower.
subulate
Narrow and tapering gradually to a fine point.
succulent
1. Juicy or fleshy.
2. A plant with a fleshy habit.
sucker
A
shoot of more or less subterranean origin; an
erect shoot originating from a bud on a root or a
rhizome, sometimes at some distance from the stem of the plant.
suffrutex
A
subshrub or undershrub.
sulcate
Furrowed; grooved. May be single (monosulcate), two (bisulcate) or many (polysulcate).
superficial
On the surface.
superior ovary
An
ovary borne above the level of attachment of the other floral parts, or above the base of a
hypanthium. Compare
inferior ovary and
half-inferior ovary.
suspended
Of an
ovule, when attached slightly below the summit of the ovary. Compare
pendulous.
suture
A junction or seam of union. See
fissure and
commissure.
sward
Extensive, more or less even cover of a surface, e.g. a lawn grass. Compare
tussock.
sympatric
Having more or less similar or overlapping ranges of distribution.
sympodial
A mode of growth in which the main axis is repeatedly terminated and replaced with a lateral branch. Examples occur in the family
Combretaceae, including the genera
Terminalia and
Combretum. Compare
monopodial.
syconium
A hollow
infructescence containing
multiple fruit, such as that of a
fig.
syn-
A prefix meaning "with, together".
symmetrical
Capable of being divided into at least two equal, mirror-image halves (e.g.
zygomorphic) or having rotational symmetry (e.g.
regular or
actinomorphic). Compare
irregular and
asymmetrical.
sympetalous
Having united (
connate or fused)
petals, not free (
apopetalous). See also
syntepalous (having fused
tepals).
symphyllous
a single perianth-whorl of united segments. Compare
gamophyllous (
synonym),
apophyllous, and
polyphyllous.
synangium
A fused aggregate of
sporangia, e.g. in the trilocular sporangia of the whisk fern
Psilotum.
synanthous
A type of growth in which new leaves and flowers appear and die back at the same time. See also
hysteranthous and
proteranthous.
synaptospermy
The dispersal of
diaspores as units, where each bears more than one seed, for example where each diaspore comprises an entire inflorescence, as in
Brunsvigia or multi-seeded fruit as in
Tribulus zeyheri. Ephemeral synaptospermy is the term for when the diaspores split into units containing fewer or single seeds each, as in most
tumbleweeds. True synaptospermy is when the diaspore generally remains entire until germination, as commonly happens in species of
Grielum.
syncarpous
(of a
gynoecium) Composed of united
carpels.
synonym
An outdated or 'alternative' name for the same taxon.
synoecious
A synonym of
bisexual.
syntepalous
Having fused
tepals. See also
sympetalous (having fused
petals).
T
Leucaena leucocephala taproot exposed in a roadcut
Cross sections of
Brazil nut seeds, showing the
tegmen and
testa
Tendrils of
Cucurbita pepo, some supporting the stem on the frame, some failing to find a point of attachment
Nerine bowdenii, showing the lack of visible
sepals, and the
inferior ovaries. The sepals are incorporated into the
corolla as
tepals.
Terete raceme of
Kniphofia shown together with a cross section of a peduncle. A:
Inflorescence; B: Terete
peduncle; C: Cross section of a terete peduncle
Gymnosporia buxifolia has true
thorns, that is, modified branches. In some species such branches are complete with buds and leaves.
Sweet potato tubers exposed, showing them to be root tubers. Morphologically, they differ from stem tubers of potatoes, for example, in that root tubers do not have
nodes that bear buds. The root tubers of some species of plants, however, can produce
adventitious buds for
vegetative reproduction.
Oxalis tuberosa, a stem tuber
Corms of
Crocosmia bear typical
tunics formed of
cataphylls growing from the
nodes of the corm. The illustration shows still-living cataphylls as white tissue, whereas the functional, hard, resistant tunic is brown.
Turbinate (spinning top-shaped) roots of sugar beet
Haworthia lockwoodii, with its leaves
turgid and green after seasonal rains, store water against the coming dry period.
Tussock grasses on mountain slopes
taproot
The primary descending
root of a plant with a single dominant root axis.
tartareous
Having a surface that is course, thick, rough, and crumbling.
taxon
A group or category in a system of biological classification.
taxonomy
The study of the principles and practice of classification.
tegmen
The inner layer of the
testa (seed coat). It develops from the inner
integument of the
ovule.
tendril
Any slender organ modified from a stem, leaf, leaflet, or
stipule and used by climbing plants to cling to an object.
tepal
A segment of a
perianth, either
sepal or
petal; usually used when all perianth segments are indistinguishable in appearance.
terete
Circular in cross-section; more or less
cylindrical without grooves or ridges.
terminal
Situated at the tip or apex.
ternate
In groups of three; of leaves, arranged in whorls of three; of a single leaf, having the
leaflets arranged in groups of three.
terrestrial
Of or on the ground; of a habitat, on land as opposed to in water (
aquatic), on rocks (
lithophytic), or on other plants (
epiphytic).
tessellate
With cracks or fissures arranged in squares so as to give a chequered appearance. Usually applied to the appearance of the bark of a tree
testa
The seed coat.
tetrad
A group of four; usually used to refer to four pollen grains which remain fused together through maturity (e.g. in the
Epacridaceae).
tetragonal
Square; having four corners; four-angled, e.g. the cross-sections of stems of herbaceous
Lamiaceae.
tetramerous
In four parts, particularly with respect to flowers; four parts in each whorl. See also
trimerous and
pentamerous.
tetraploid
Having four complete sets of chromosomes in each
sporophyte cell.
tetraspore
The asexual spore of
red algae. It is so named because each
sporangium produces just four spores. See
Rhodophyceae.
thalamus
1. A synonym for
receptacle.
2. The inflorescence disk of members of the
Asteraceae.
3. A
calyx, as used by
Carl Linnaeus.
having a
thallus-like structure; in the form of a thallus; thalloid
thallus
A vegetative structure that is not differentiated into stem and leaves, as in
lichens,
algae,
thallose liverworts, and certain
vascular plants, e.g.
Lemna
theca
One of the usually two
synangia in which pollen is produced in flowering plants. It consists of two fused
sporangia known as
pollen sacs. The wall between the pollen sacs disintegrates before dehiscence, which is usually by a common slit.
thorn
A sharp, stiff point, usually a
modified stem, that cannot be detached without tearing the subtending tissue; a spine. Compare
prickle.
throat
The opening of a
corolla or
perianth.
thyrse
A branched inflorescence in which the main axis is indeterminate (
racemose) and the lateral branches determinate (
cymose).
tomentellous
Minutely tomentose.
tomentum
A dense covering of short, matted hairs.
Tomentose is often used as a general term for bearing an
indumentum, but this is not a recommended use.
toothed
Having a more or less regularly incised
margin.
torus
See
receptacle.
transmitting tissue
See
pollen transmitting tissue.
trapeziform
1. Like a
trapezium (a four-sided figure with two parallel sides of unequal length).
2. Like a trapezoid (a four-sided figure, or
quadrilateral, with neither pair of sides equal); sometimes used erroneously as a synonym for
rhombic.
tree
A woody plant, usually with a single distinct
trunk and generally more than 2–3 metres (6.6–9.8 ft) tall.
triad
A group of three.
triangular
Planar and with 3 sides.
tribe
A taxonomic grouping that ranks between
genus and
family.
trichome
In non-filamentous plants, any hair-like outgrowth from the
epidermis, e.g. a hair or bristle; sometimes restricted to unbranched epidermal outgrowths.
trichotomous
3-forked or branched into three. Compare
dichotomous.
trifid
Split into three parts. See also
bifid.
trifoliate
A
compound leaf of three
leaflets; for example, a
clover leaf.
trifoliolate
See
trifoliate.
trigonous
Triangular in cross-section and obtusely angled. Compare
triquetrous.
trimerous
In three parts, particularly with respect to flowers; having three parts in each whorl. See also
tetramerous and
pentamerous.
trinerved
Having three
nerves or
veins.
triplinerved
(of leaves) Having three main nerves with the lateral nerves arising from the midnerve above the base of the leaf.
triporate
(of pollen) Having three pores.
triquetrous
More or less triangular in cross-section, but acutely angled (with 3 distinct longitudinal ridges). Compare
trigonous.
trivalve
Divided into three
valves. Also trivalvar. See also
bivalve.
trivial name
The second word in the two-part scientific name of an organism. Compare
specific epithet.
trophophyll
A vegetative, nutrient-producing leaf or
microphyll whose primary function is
photosynthesis. It is not specialized or modified for some other function. Compare
sporophyll.
trullate
Ovate but angled, as with a bricklayer's
trowel; inversely
kite-shaped. Compare
rhombic.
truncate
Cut off squarely; having an abruptly transverse end.
trunk
The upright, large and typically woody main
stem of a tree.
truss
A compact cluster of flowers or fruits arising from one center; evident in many
rhododendrons.
tuber
Any of many types of specialized vegetative underground storage organs. They accumulate food, water, or in protection from death by fire, drought, or other hard times. Tubers generally are well differentiated from other plant organs; for example, informally a carrot is not generally regarded as a tuber, but simply a swollen root. In this they differ from the tuber of a sweet potato, which has no special root-like function. Similarly,
corms are not generally regarded as tubers, even though they are underground storage stems. Tubers store food for the plant, and also have important roles in
vegetative reproduction. They generally are of two main types: stem tubers form by the swelling of an underground stem growing from a root, or from structures such as underground
stolons. Stem tubers generally produce propagative buds at their stem
nodes, forming a seasonal
perennating organ, e.g. a
potato. The main other class is the root tuber, also called
tuberoid. They differ from stem tubers in features such as that, like any normal root, they do not form nodes.
tubercle
A small
wart-like outgrowth or protuberance of tissue.
tuberculate
Covered in
tubercles. See
warty.
tuberoid
An alternative name for underground storage organ formed by the swelling of a root; occurs in many
orchids.
tuberous
Resembling a
tuber or producing tubers.
tubular
Having the form of a tube or
cylinder.
tufted
Densely
fasciculate at the tip.
tunic
The outer covering of some
bulbs and
corms.
tunicate
(of
bulbs) Consisting of concentric coats.
turbinate
Shaped like a
spinning top or
beetroot.
turgid
Swollen with liquid; bloated; firm. Compare
flaccid.
tussock
A dense tuft of vegetation, usually well separated from neighbouring tussocks, for example in some grasses. Compare
sward.
two-ranked
Having leaves arranged in two rows in the same plane, on opposite sides of the branch. See
distichous.
type
An item (usually an
herbarium specimen) to which the name of a taxon is permanently attached, i.e. a designated representative of a plant name. Important in determining the priority of names available for a particular taxon.
type genus
In nomenclature, a single
genus on which a taxonomic
family is based.
U
Umbo in the middle of the cap of
Cantharellula umbonata
Thorny
prickles of
Senegalia mellifera subspecies detinens are
unciform.
Mammillaria bocasana has
uncinate tips on its major
spines.
Pitchers of the species
Nepenthes ventricosa tend to be markedly
urceolate.
umbel
A
racemose inflorescence in which all the individual flower stalks arise in a cluster at the top of the
peduncle and are of about equal length; in a simple umbel, each stalk is unbranched and bears only one flower. A
cymose umbel looks similar to an ordinary umbel but its flowers open centrifugally.
umbo
A rounded elevation, such as in the middle of the top of an umbrella or
mushroom; a central boss or protuberance, such as on the
scale of a
cone.
umbonate
Having an
umbo, with a conical or blunt projection arising from a flatter surface, as on the
top of a mushroom or in the scale of a pine
cone.
unciform
Hook-shaped.
uncinate
Having a hook at the apex.
undershrub
A low
shrub, often with flowering branches that die off in winter. Compare
subshrub.
understory
Plant life growing beneath the forest
canopy.
undulate
Wavy and not flat. Compare
sinuate.
uniflor
Having a single flower (uniflory). Compare
pauciflor (few) and
pluriflor (many).
unilocular
Having one
loculus or chamber, e.g. the ovary in the families
Proteaceae and
Fabaceae.
uniserial
Arranged in a single row or series. Unbranched.
Uniseriate.
uniseriate
Arranged in a single row or series. Unbranched.
Uniserial.
unisexual
Of one sex; bearing only male or only female reproductive organs,
dioecious,
dioicous. See
Sexual reproduction in plants.
unitegmic
(of an
ovule) Covered by a single
integument. See also
bitegmic, having two integuments.
urceolate
Shaped like an
urn or
pitcher, with a swollen middle and narrowing top. Examples include the pitchers of many species of the
pitcher plant genera
Sarracenia and
Nepenthes.
usu.
An abbreviation of usually. Compare
s.t. and
oft..
utricle
1. A small bladder; a
membranous bladder-like sac from the ovary wall, thin pericarp, becomes more or less bladdery or inflated at maturity enclosing an
ovary or fruit.
2. In
sedges, a fruit in which the fruit is loosely encloses from a modified tubular bract, see
perigynium.
V
Photomicrograph of a cross section of a
vascular bundle in the stem of a typical
herbaceous dicotyledon A: Phloem
B: Cambium
C: Xylem
D: Fibrous sheath of vascular bundle
Leaf
veins and
velutinous hairs of
Nepeta
Velamen, the pale grey membrane covering the mature part of the root of an
epiphyte
Flower stalks and sepal tubes of
Pueraria phaseoloides are covered with
velutinous (
velvety) hairs.
Verticillaster of
Salvia yangii
Verticillate leaves and emerging branchlets of a
forb
Vestigial leaf scales on stem
nodes of
Viscum capense
Asparagus virgatus owes its
specific epithet virgatus to the twiggy appearance of its
virgate shoots.
vallecular canal
A resin canal coinciding with a longitudinal groove in the seeds of
Asteraceae. A longitudinal cavity in the cortex of the stems of
Equisetum, coinciding with a groove in the stem surface.
valvate
(of sepals and petals in bud) Meeting edge-to-edge but not overlapping.
valve
A portion of an organ that fragments or splits open, e.g. the teeth-like portions of a
pericarp in a split (dehisced)
capsule or
pod when ripe.
var.
An abbreviation of
varietas.
variant
A plant or group of plants showing some measure of difference from the characteristics associated with a particular
taxon.
variegated
Irregularly marked with blotches or patches of another color.
varietas
A taxonomic rank below that of
species and between the ranks of
subspecies and
form.
vascular
Referring to the conducting tissues (
xylem and
phloem) of
vascular plants.
vascular bundle
A bundle of
vascular tissue in the primary stems of
vascular plants, consisting of specialized conducting cells for the transport of water (
xylem) and assimilate (
phloem).
vasculum
A container used by botanists for collecting field specimens.
vein
A strand of
vascular tissue, e.g. in the leaves of
vascular plants.
veinlet
A small
vein; the ultimate (visible) division of a vein.
velamen
A spongy tissue covering the
aerial roots of
orchids and some other
epiphytes.
velutinous
See
velvety.
velvety
Densely covered with fine, short, soft, erect hairs.
venation
The arrangement of
veins in a leaf.
ventral
From Latin
venter, meaning "belly". The opposite of
dorsal. Partly because the term originally referred to animals rather than plants, usage in botany is arbitrary according to context and source. In
general "ventral" refers to "the belly or lower part", but in
botanical usage such concepts are not always clearly defined and may be contradictory. For example:
- facing toward the axis (adaxial) in referring to a lateral organ of an erect plant
- facing toward the substrate in any part of an erect plant, for example the lower surface of a more or less horizontal leaf (abaxial)
- facing toward the substrate in a prostrate or climbing plant.
For more detail see
dorsal.
vernation
The arrangement of unexpanded leaves in a
bud; the order in which leaves unfold from a bud.
vernicose
Having a shiny or polished surface as if covered in varnish and a slick or smooth texture.
vernonioid
In the family
Asteraceae, style with sweeping hairs borne on abaxial surfaces of style branches.
verruciform
Wart-like in form.
verrucose
Having warts.
verruculose
Minutely
verrucose; minutely warty.
versatile
(of
anthers) Swinging freely about the point of attachment to the
filament.
verticillate
Arranged in one or more
whorls, i.e. several similar parts arranged at the same point of the
axis, e.g. leaf arrangement. Compare
pseudoverticillate (appearing whorled or verticillate but not actually so).
verticillaster
A type of
pseudoverticillate inflorescence, typical of the
Lamiaceae, in which pseudo-whorls are formed from pairs of opposite
cymes.
vesicular
(of hairs) Bladder-like; vesciculous, bearing such hairs.
vessel
A capillary tube formed from a series of open-ended cells in the water-conducting tissue of a plant.
vestigial
Reduced in form and function from the normal or ancestral condition.
villosulous
Minutely villous.
villous
Abounding in or covered with long, soft, straight hairs; shaggy with soft hairs.
vine
1.
Scandent plants
climbing by means of trailing or twining stems or
runners.
2. Such a stem or runner.
3. A member of the genus
Vitis.
virgate
Wand-shaped, twiggy, especially referring to erect, straight stems. In
mycology, referring to a
pileus with radiating ribs or lines.
Viridiplantae
A clade of
autotrophic organisms that includes the
green algae,
Charophyta and
land plants, all of which have
cellulose in their
cell walls,
chloroplasts derived from primary
endosymbiosis with
cyanobacteria that contain
chlorophylls a and
b and lack
phycobilins.
viscid
Sticky; coated with a thick, syrupy secretion.
vitta
An oil tube in the fruit of some plants.
viviparous
1. Referring to seeds or fruits which germinate before being shed from the parent plant.
2. The development of plantlets on non-floral organs, e.g. leaves.
W
Watershoots
The
verticillate whorls of leaves on
Brabejum stellatifolium are unusual among trees in its native region.
Winged seeds of
Catalpa bignonioides are nearly all wing. Tufts at the tips increase aerodynamic
drag, thereby improving wind dispersal.
Leaves of some species of
Citrus have winged petioles.
Senecio haworthii leaves have an unusually dense
wooly coat.
warty
A surface covered with small round protuberances, especially in fruit, leaves, twigs and bark. See
tuberculate.
watershoot
An
erect, strong-growing, or
epicormic shoot developing from near the base of a shrub or tree, but distinct from a
sucker.
weed
1. Any plant growing where it is not wanted; commonly associated with disrupted habitats. See also
ruderal.
2. An unwanted plant which grows among agricultural
crops.
3. A naturalised, exotic, or ecologically "out-of-balance" indigenous species outside of the agricultural or garden context, which, as a result of invasion, adversely affects the survival or regeneration of indigenous species in natural or partly natural vegetation communities.
wild
Originating from a known wild or purely natural habitat (
wilderness).
whorl
A ring of organs borne at the same level on an
axis (e.g. leaves,
bracts, or floral parts).
wing
1. A membranous expansion of a fruit or seed which aids in dispersal, for instance on
pine seeds.
2. A thin flange of tissue extending beyond the normal outline of a structure, e.g. on the column of some
orchids, on stems, on petioles.
3. One of the two lateral petals of a flower of subfamily
Faboideae of family
Fabaceae, located between the
adaxial standard (banner) petal and the two
abaxial keel petals.
woody
hard and
lignified; not
herbaceous
wooly
woolly
Very densely covered with long, more or less matted or intertwined hairs, resembling a sheep's
wool.
X
xeromorph
A plant with structural features (e.g. hard or succulent leaves) or functional adaptations that prevent water loss by evaporation; usually associated with arid habitats, but not necessarily drought-tolerant. Compare
xerophyte.
xerophyte
A plant generally living in a dry habitat, typically showing xeromorphic or succulent adaptation; a plant able to tolerate long periods of drought. Compare
xeromorph.
xylem
A specialized water-conducting tissue in
vascular plants.
Z
Zonate markings on the leaves of a garden variety of
Pelargonium zonale
Like most of the genus
Pelargonium, and unlike most members of the genus
Geranium,
Pelargonium quercifolium bears flowers that are
bilaterally symmetrical. Accordingly, because the yoke of an ox is bilaterally symmetrical, such flowers are said to be
zygomorphic, which literally means "yoke-shaped".
zonate
Having light and dark circular bands or rings, typically on leaves or flowers.
zygomorphic
Bilaterally symmetrical; symmetrical about one vertical plane only; applies to flowers in which the
perianth segments within each whorl vary in size and shape. Contrast
actinomorphic and
irregular.
zygote
A fertilized cell, the product of fusion of two
gametes.
See also
References
- ^ Turland et al. 2018, Article 18.
- ^ Copied definition from Wiktionary entry for faculative biology adjective. See that page's history for attribution.
- ^ Copied definition from Wiktionary entry for fimbriate biology adjective. See that page's history for attribution.
- ^ "Glossary: P". Go Botany. Native Plant Trust. Archived from the original on 28 September 2023. Retrieved 4 January 2024.
- ^ "tuberculate". Dictionary of botany. Retrieved 7 January 2024.
- ^ Carr, G.W., in Foreman & Walsh, 1993.
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External links
Royal Botanical Gardens at Kew
Australia and New Zealand
Africa