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Botanical Glossary

Батанічны Гласарый Belorussian translation of this Botanical Glossary

An alphabetical listing of over 800 botanical terms and their meanings, helpfully hypertexed for rapid reference.


abaxial to buttress
caducous to extrorse
facultative to juvenile
karyoevolution to ovulode
palea to runner
sac to zygomorphic

abaxial: (dorsal) of the side or surface of an organ, facing away from the axis. cf. adaxial.
abscission: the normal shedding from a plant of an organ that is mature or aged, e.g. a ripe fruit, an old leaf. adj. abscissile.
accessory fruit: a fruit, or group of fruits derived from one flower, in which the conspicuous, fleshy portion develops from the receptacle and is shed with the true fruit(s) attached.
accrescent: increasing in size with age, as the calyx of some plants after flowering.
accumbent: of the orientation of an embryo, with the radicle lying against the edges of the two cotyledons.

achene: a dry, indehiscent fruit formed from a superior ovary of one carpel and containing one seed which is free from the pericarp. Lactuca viminea (often applied, less correctly, to the one-seeded fruits of Asteraceae). cf. cypsela.
acicular: needle-shaped and stiff.

aciculate: finely scored on the surface, as if scratched by a pin. Needle like.
acropetal: arising or developing in a longitudinal sequence beginning at the base and proceeding towards the apex. cf. basipetal.
acrostichoid: of sporangia, densely covering the abaxial surface of the fertile frond, i.e. not in distinct groups; of ferns, having the sporangia arranged as above.
actinomorphic: of flowers, symmetrical about more than one vertical plane. cf. zygomorphic.
aculeate: prickly.

acuminate: tapering gradually to a protracted point.
acute: terminating in a distinct but not protracted point, the converging edges separated by an angle less than 90 degrees.
adaxial: facing towards the axis. cf. abaxial.
adnate: fused along the whole length to an organ of a different kind, e.g. applied to a stamen fused to a petal.
adventitious: arising in abnormal positions, e.g. roots arising from the shoot system, buds arising elsewhere than in axils of leaves.
adventive: introduced recently, in particular since colonisation by man. cf. introduced.
aerenchyma: tissue incorporating large, gas-filled spaces interspersed with the cells in a characteristic pattern.
aestivation: the arrangement of sepals and petals or their lobes in an unexpanded flower bud. cf. vernation.

aggregate fruit: a cluster of fruits formed from the free carpels of one flower. cf.syncarp.
allopatric: of two or more species, having different ranges of distribution. cf. sympatric.
alternate: of leaves or other lateral organs, borne singly at different heights on the axis; of floral parts, on a different radius, e.g. describing the position of stamens with respect to petals. cf. opposite.
alveolate: pitted or honeycombed on the surface.

amant: or catkin, elongated cluster of single-sex flowers bearing scaly bracts and usually lacking petals.
amplexicaul: of a leaf base, stem-clasping.
anastomosis: fusion to form a network e.g. of veins in a leaf blade.
anatropous: of an ovule, inverted so that the micropyle faces the placenta.
androdioecious: a species having two forms; one with bisexual flowers and the other with male flowers.
androecium: the stamens of one flower collectively.
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.
andromonoecious: having bisexual and male flowers on the same plant.
androphore: a stalk bearing the androecium.
anemophilous: pollinated by wind.
angiosperm: a seed-bearing plant whose ovules, and hence seeds, develop within an enclosed ovary. cf. gymnosperm.
angustiseptate: with narrow partitions, cf. latiseptate.
annual: A plant that germinates, flowers and fruits within a single year. Characteristic features are that it does not have the remains of old growth at the base, nor rhizomes or stolons.
annular: arranged in or forming a ring.
annulus: a ring; in ferns, the elastic ring of cells, forming part of the sporangium wall, that initiates dehiscence.
anterior: of floral organs, on the side of the flower farthest from the axis. cf. posterior.
anther: the pollen-bearing part of a stamen. cf. filament.
antheridium: the fertile organ of a male gametophyte or the male organ of a bisexual gametophyte, in which male gametes are formed.
anthesis: the time of opening of a flower.
anthocarp: a false fruit consisting of the true fruit and the base of the perianth, as in Nyctaginaceae.
antipetalous: inserted in front of the petals; opposite the petals.
antisepalous: inserted in front of the sepals; opposite the sepals.
antrorse: directed forwards or upwards. cf. retrose.
apex: terminal, growing point, tip of leaves, stem, roots.
apetalous: without petals.
apical: at the apex or point of any structure.
apiculate: terminating in a short, sharp, flexible point.
apiculum: a short, abrupt, flexible point, adj. apiculate.
apocarpous: of a gynoecium, consisting of two or more carpels which are free from one another or almost so.
apomict: a plant that produces viable seed without fertilisation.
appendage: a structure arising from the surface or extending beyond the tip of another structure.
appressed: pressed closely together but not united with.
approximate: close together but not united.
aquatic: living in or on water for all or a substantial part of the life span (generally restricted to fresh/inland waters).
arborescent: resembling a tree (applied to non-woody plants attaining tree height and to shrubs tending to become tree-like in size). cf. dendroid.
arching: curved like a bow.
arcuate: curved like a bow.
areole(adj.areolate): a space between the threads of a net; in Cactaceae, a cluster of hairs/spines/bristles borne at the node of a leafless stem; in Mimosaceae (for example), a distinct, oblong or elliptical area on the face of a seed, bounded by a fine line.
aril: a structure partly or wholly covering the testa of a seed and formed by expansion of the funicle. adj. arillate.
aristate: having a stiff, bristle-like awn or tip.
aristulate: having a small awn.
aromatic: possessing a distinctive smell or taste.
article: a segment of a jointed stem or of a fruit with constrictions between the seeds.
articulate: jointed; having joints where separation may occur naturally; of a stem, having nodes.
ascending: growing erect after an oblique or semi-horizontal beginning.
asexual: not forming part of a cycle which involves fertilisation and meiosis.
asperulate: slightly rough to the touch. Perceptibly knobbly.
attenuate: tapering gradually and evenly.
auricle: an ear-shaped appendage at the base of a leaf, leaflet or corolla lobe. adj. auriculate.
autochthonous: of the inhabitants of a region, original; earliest known; (applied to an element of the australian flora rich in endemics and believed to have been evolving in australia for a long period of time).
autotrophic: independent of other organisms in respect of organic nutrition; able to fix carbon dioxide, by photosynthesis, to form carbohydrates.
awn: a bristle-like appendage, e.g. on the tip or back of the lemma of a grass floret.
axil: the angle between a leaf or bract and the axis bearing it. adj. axillary.
axile: on an axis; of a placenta, on the central axis of the ovary.
axillary: growing in an axil, between an axis and any organ which arises from it.
axis: a stem, (commonly used for the main stem of a whole plant or of an inflorescence).
baccate: berry-like; of seeds, having a succulent or pulpy testa; of fruits, having the seeds embedded in pulp.
barbellae: short, straight, stiff hairs or barbs.
barbulae: in scaevola, outgrowths on the margin of the wings or in the throat of the corolla; they may be simple or have apical hairs or papillae.
basal: at the base; of a placenta, at the base of the ovary.
basifixed: attached at or by the base, e.g. of anthers, by the base of the connective.
basipetal: developing, in sequence, from the apex towards the base. cf. acropetal.
basiscopic: pointing towards the base (applied to the first lateral vein of a leaflet on the side nearer the leaf base).
bathyphyll: a leaf at the base of a stem with the function of attachment to a substrate.
beak: a prominent terminal projection, especially of a carpel or fruit.

berry: a fleshy or pulpy indehiscent fruit with the seed(s) embedded in the fleshy tissue of the pericarp. cf. drupe, pyrene.
biennial: a plant whose life span extends for more than one but less than two years after germination.
bifacial: of leaves, flat or channelled with distinct adaxial and abaxial surfaces.
bifid: divided, for about half the length, into two parts. cf. bipartite.
bifoliate: of plants, having two leaves.

bifoliolate: of leaves, having two leaflets
bilabiate: two-lipped, e.g. of a corolla in which fusion of an anterior group and a posterior group of petals extends beyond the top of the corolla tube.
bilocular: having two cavities.
bipartite: divided, nearly to the base, into two parts. cf. bifid.

bipinnate: of leaves, twice pinnately divided. cf. pinnate, tripinnate.
biseriate: arranged in two rows or whorls.

biserrate: margins having serrations along the serrations; doubly serrate.
bisexual: bearing both male and female organs together, e.g. on the same gametophyte or in the same flower.
blade: the expanded part of a leaf or petal.
bole: the trunk of a tree, below the lowest branch. cf. canopy.
brachyblast: a short branch; a spur shoot.
bract: a leaf-like structure, different in form from the foliage leaves and without an axillary bud, associated with an inflorescence or flower.
bracteole: a small bract-like structure borne singly or in pairs on the pedicel or calyx of a flower.
broom-like: with many branches parallel or almost so and usually erect, as in spartium (spanish broom).
bulb: a storage organ, usually underground, made up of a stem and leaf bases, the food reserves being stored in the inner, fleshy leaf bases.
bulbel: a bulb arising from another bulb.
bulbil: a small, deciduous bulb (or tuber) formed in the axil of a leaf and functioning to propagate the plant vegetatively.
bulbil: a small deciduous bulb replacing flowers in an inflorescence, and functioning to propagate the plant vegetatively.
bulblet (= bulbel): a small bulb arising from another bulb.

burr: a rough or prickly propagule consisting of a seed or fruit and associated floral parts or bracts.
buttress: a flange of tissue protruding from the main outline of the base of a tree.
caducous: falling off early.
caespitose: growing in tufts.
calli: in dampiera small outgrowths in the throat of the corolla (acting as tactile guides for pollinators).
callus: a protruding mass of hardened tissue, often formed after an injury but sometimes a regular feature of the plant, e.g. on the labellum of some orchids and the axis of the spikelet of some grasses. adj. callose.
calyptra: in mosses, a cap-like structure covering or partly covering the capsule and derived from the neck of the archegonium. (in a flower, = operculum).
calyx-tube: a tube formed by fusion or cohesion of sepals. cf. hypanthium.
calyx: the sepals of one flower collectively.

campanulate: bell-shaped.
campylotropous: of an ovule, orientated transversely, i.e. with its axis at right angles to its stalk, and with a curved embryo sac.
canaliculate: with a longitudinal groove or channel.
canopy: the branches and foliage of a tree. cf. bole.
capitate: of an inflorescence, with the flowers unstalked and aggregate into a dense cluster; of a stigma, globose, like the head of a pin.
capitellate: shaped like, or aggregate into, a very small head.
capitulum: a dense cluster of sessile flowers.

capsule: a dry fruit formed from two or more united carpels and dehiscing at maturity to release the seeds.
carinate: keeled.
carpel: an organ at the centre of a flower, bearing one or more ovules and having its margins fused together or with other carpels to enclose the ovule(s) in an ovary, and consisting also of a stigma and usually a style.
carpophore: in ferns, the stalk of a sporocarp; in a fruit, the stalk of a mericarp.
caruncle (= strophiole): an outgrowth of a seed coat (testa), near the hilum.
caryopsis: a dry, indehiscent, one-seeded fruit in which the seed coat (testa) is closely fused to the fruit wall (characteristic of grasses).
cataphyll: a scale leaf associated with a vegetative part of a plant, e.g. rhizome, perennating bud.

catkin: or amant, a raceme, or spike, in which the flowers are unisexual and without conspicuous perianth.
caudate: having a narrow tail-like appendage.
caudex: a thick, erect trunk, especially of cycads.
caudicle: a thread to which a pollen mass is attached in Orchidaceae and Asclepiadaceae.
cauliflorous: see cauline.
cauline: of leaves, borne on an aerial stem; of flowers or fruits, (= cauliflorous) borne on old wood.
cell: the basic unit of plant structure consisting, at least when young, of a protoplast surrounded by a wall.
cellulose: the compound from which a plant's cell walls are made. Most of the parts of plants that we can see and touch are cellulose. Cellulose is the plant fibers used in fabrics, paper and cardboard, roughage (fiber) in food and the main substance that combusts when plants are burnt.
centrifugal: directed, or developing, from the centre or axis outwards.
centripetal: directed, or developing, from the outside towards the centre or axis.
cernuus, cernua, cernuum: of flowers, nodding; neither vertically upright nor pendulous, but usually inclined slightly down from the horizontal.
chaff: thin, membranous scales or bracts; thin, dry unfertilised ovules among the fully developed seeds of a fruit.
chalaza: the part of an ovule to which the end of the stalk (funicle) is attached.
chartaceous: papery.
chlorophyll: pigment(s) constituting the green colouring matter of plants and absorbing radiant energy in photosynthesis.
chromosome: a thread-like structure in the nucleus of a cell, containing a linear sequence of genes.
cilia: in unicellular plants, gametes, spores etc., minute hair-like protoplasmic protrusions whose movement confers motility on the cell; in higher plants, hairs more or less confined to the margins of an organ. sing. cilium; adj. ciliate.
cincinnus: a monochasial, cymose inflorescence with flowers arising alternately from one side of an axis then the other; a spirally curled cymose inflorescence.
circinnate (= circinate): spirally coiled, with the tip innermost.
circumsciss: (to) break open along a transverse line around the circumference. adj. circumscissile.
cladode: the photosynthetic stem of a plant whose foliage leaves are absent or much reduced. cf. phyllode.
cladophyll: a flattened, leaf-like photosynthetic stem not bearing leaves or scales. cf. phylloclade.
class: a major taxonomic rank, between order and division.
clavate: club-shaped.
claw: a narrow, stalk-like basal portion of a petal, sepal or bract.
cleft: divided almost to the midvein.
cleistogamous: of flowers, self-pollinating and setting fertile seed but never opening.
climber: any plant that climbs. cf. liane, scandent, tendril.
clone: a set of organisms produced from one parent by vegetative reproduction.
coccus: a one-carpel unit of a schizocarp or lobed fruit.
coccus: one of the (usually 1-seeded) lobes of a distinctly lobed fruit, becoming separate at maturity. pl. cocci.
cochlear: of the arrangement of corolla lobes in a bud, a variant of imbricate aestivation.
cochleate: coiled like a snail-shell.
cohesion: the sticking together of floral parts of the same whorl without organic fusion. adj. coherent.
collateral: situated side by side; adjacent and on the same radius of an axis.
colliculate: covered with small, rounded or hillock-like elevations (colliculae).
colporate: of a pollen grain, having both an elongated and a rounded aperture. cf. porate.
columella: the central axis of a moss capsule; sometimes applied to the central axis of fruits and cones.
column: (in grasses see; gynostemium), a structure in orchidaceae, asclepiadaceae and stylidiaceae, extending above the ovary of a flower and incorporating stigma, style and stamens.
coma: a tuft, especially of hairs on a seed.
coma: a tuft of hairs. adj. comose.
commissure: a join or seam; the interfacing of two fused carpels in an ovary.
complicate: of leaves, the lamina (or part of the lamina) folded upon itself.
compound: of a leaf, having the blade divided into two or more distinct leaflets; of an inflorescence, made up of an aggregate of smaller inflorescences.
compressed: flattened in one plane, either dorsally (bringing the front and back closer together) or laterally (bringing the sides closer together).
concolorous: coloured uniformly; the same colour on both sides. cf. discolorous.
concolorous: of uniform colour; of leaves, having both surfaces the same colour.
conduplicate: folded together, with the fold-line along the long axis (e.g. of cotyledon in a seed).

cone: in gymnosperms and club-mosses, a group of sporophylls arranged compactly on a central axis.
(Loosely) in Casuarina, a woody multiple fruit incorporating the bracts and bracteoles associated with the flowers.
conflorescence: a compound inflorescence consisting of two or more unit inflorescences.
conflorescence: a flower-bearing branch system in which the main axis does not end in a flower but the axes of the branches do.
connate: fused to another organ (or other organs) of the same kind.
connective: the part of an anther that connects the lobes.
connivent: coming into contact; converging.
contorted: see convolute.
convolute: of the arrangement of corolla lobes in a bud, a form of imbricate aestivation in which each segment has one edge overlapping the adjacent segment, like a furled umbrella.

cordate: of a leaf blade, broad and notched at the base; heart-shaped.
cordiform: shaped like a heart (in three dimensions).
coriaceous: leathery.
corm: a fleshy, swollen stem base, usually underground, in which food reserves are stored between growing seasons.
corniculate: bearing, or terminating in, one or more small horns.
corolla: the petals of a flower collectively.
corona: a ring of tissue arising from the corolla or perianth of a flower and standing between the perianth lobes and the stamens.
corona: a ring of tissue derived from the perianth or filaments of a flower, and standing between the perianth lobes and the stamens.
cortex: the region of a stem or root surrounding the vascular cylinder but inside the epidermis.
corymb: a racemose inflorescence in which the pedicels of the lower flowers are longer than those of the flowers above, bringing all flowers to about the same level.
cotyledon: the primary leaf (or one of two or more primary leaves) of an embryo.

crenate: with small, rounded teeth; scalloped.

crenulate: minutely scalloped.
crown: the part of a tree or shrub above the level of the lowest branch.
crustaceous: brittle; of marine algae, encrusted with calcium carbonate.
cryptogam: (literally) a plant whose sexual reproductive parts are not conspicuous; a plant that produces spores, not seeds, in its sexual reproductive cycle, e.g. ferns, mosses, algae. cf. phanerogam.
cucullate: hooded; hood-shaped.
culm: an aerial stem, in grasses, sedges, rushes, etc., bearing the inflorescence.

cuneate: wedge-shaped.
cupuliform: nearly hemispherical, cupola-shaped.
curvinerved: with curved parallel veins.
cushion, floral: a swollen floral axis on which several small flowers are borne.
cuspidate: tapering into a sharp, rigid point.
cut: acutely divided at least halfway to the midvein.
cyathium: an inflorescence of unisexual flowers surrounded by involucral bracts, as in euphorbia.
cyclic: of floral organs, several borne at the same level on the axis; whorled. cf. spiral.

cyme: an inflorescence in which each flower, in turn, is formed at the tip of a growing axis and further flowers are formed on branches arising below it.
cymule: a diminutive cyme, usually few-flowered.
cypsela: a dry, indehiscent, one-seeded fruit formed from an inferior ovary. cf. achene.

cystolith: a stalked structure growing from a cell wall into the cell cavity, encrusted with calcium carbonate.
deciduous: falling seasonally, e.g. of the leaves or bark of some trees.
declinate: bent downwards or forwards.
decompound: more than once compound.
decumbent: spreading horizontally but then growing upwards.
decurrent: extending downwards beyond the point of insertion, e.g. of a lamina extending downwards to form a flange along the petiole.
decussate: in pairs, with successive pairs borne at right angles to each other.
definite: of a constant number; of stamens, twice as many as the petals or sepals, or less; of an inflorescence, ending in a flower or an aborted floral bud.
deflexed: bent downwards.
deflexed: bent outwards. cf. inflexed.
dehiscent: breaking open at maturity to release the contents.

deltoid: triangular with the sides of about equal length.
dendroid: tree-like in form but not in size. cf. arborescent.
dentate: toothed.
denticulate: finely toothed.
depressed: flattened as if pressed down from the top or end.
determinate: of growth or branching, with a bud or flower terminating the growth of the main axis; of an inflorescence, see definite.
diadelphous: having the stamens united into two groups, or all but one united in a group and one free.
diaphanous: extremely thin and transparent.
dichasium: a cymose inflorescence with opposite branching below the flower which terminates each axis. cf. monochasium.
dichlamydeous: of a flower, having two whorls of perianth parts.
dichotomous: forking into two equal branches resulting from division of the growing point.
diclinous: having the stamens and the carpels in separate flowers.
dicotyledon: a flowering plant whose embryo has two (rarely more) cotyledons (seed leaves). cf. monocotyledon.
didymous: borne in pairs; of anthers, having two lobes, with scarcely any tissue connecting them.
didynamous: of stamens, four in number, two being distinctly longer than the other two.
digitate: branching from the axis or stalk like the fingers of a hand.
dimorphic: of two different forms.
dioecious: having the male and female reproductive structures on separate plants. cf. monoecious.
diplecolobous: of cotyledons in a seed, twice folded transversely.
diploid: having two of the basic sets of chromosomes in the nucleus. cf. haploid, polyploid.
disc: a plate or rim of tissue, derived from the receptacle of a flower, occurring between whorls of floral parts.
discolorous: variegated; coloured differently on different sides. cf. concolorous.
dissepiment: a partition (septum) within an ovary or fruit, derived by fusion of adjacent carpels.
distal: remote from the point of origin or attachment. cf. proximal.
distichous: arranged in two rows on opposite sides of a stem and thus in the same plane.
diurnal: of flowers, opening only during daylight hours.
divaricate: widely spreading.
division: the major taxonomic rank within the plant kingdom (in which the phylum is no longer generally recognised). cf. phylum.
divided: separated, cut, cleft, lobed, parted
domatia: small structures on the lower surface of a leaf in some woody dicotyledons, usually consisting of depressions, partly enclosed by leaf tissue or hairs, located in the axils of the primary veins. sing. domatium.
dorsal: of a lateral organ, (relating to the side) facing away from the axis, i.e. the 'back'; of a thallus, facing away from the substratum. cf. ventral.
dorsifixed: attached at or by the back.
dorsiventral: having structurally different upper and lower surfaces.

drupe: a succulent fruit formed from one carpel, having the seed(s) enclosed in an inner stony layer of the fruit wall. adj. drupaceous (which is often used to mean drupe-like but not strictly a drupe). cf. berry, pyrene.
duplicate: folded twice.
echinate: bearing stiff, stout, prickly hairs.
edaphic: pertaining to the soil.
eglandular: without glands.
elaiosome: an appendage of a seed, usually rich in oil, not essential for the viability of the seed but attractive to fauna (especially ants) as a food for larvae etc. and hence an aid to dispersal by such fauna.
elater: an elongated, spirally thickened, hygroscopic cell in the capsule of a liverwort, derived from sporogenous tissue and assisting in spore dispersal; an appendage to the spore of equistem.

elliptic: oval in outline, widest at the centre.
emarginate: having a broad, shallow notch at the apex.
embryo: a young plant contained within an archegonium or seed.
enation: an epidermal outgrowth.
endemic: having a natural distribution confined to a particular geographical region.
endocarp: the innermost layer of the wall of a fruit; in a drupe, the stony layer surrounding the seed.
endosperm: nutritive tissue in a seed, in angiosperms triploid and formed in the embryo sac after fertilisation, in gymnosperms haploid and derived from the sterile portion of the female gametophyte. cf. perisperm.
ensiform: ensiform sword shaped, as the leaf of an Iris
entire: having a smooth margin, not dissected or toothed.
entomophilous: pollinated by insects.
ephemeral: short-lived.
epicalyx: a whorl of bracts, just below a flower, looking like a second calyx.
epicarp: the outer layer of the wall of a fruit, i.e. the 'skin'.
epicormic: of buds, shoots or flowers, borne on the old wood of trees (applied especially to shoots arising from dormant buds after injury or fire).
epicortical: on top of the bark, i.e. outside the bark.
epicotyl: outside or beyond the cotyledon(s), in hypogeal germination the seedling's stem growth is epicotyl.
epidermis: the outermost layer of cells of an organ, usually only one cell thick.
epigeal: of germination, having the cotyledon(s) emerging from the seed coat (testa) and becoming photosynthetic. cf. hypogeal
epigynous: of floral parts (especially stamens), attached above the level of insertion of the ovary, and arising from tissue that is fused to the ovary wall. cf. hypogynous, perigynous.
epipetalous: borne on the petals.
epiphyllous: growing on leaves, e.g. applied to vegetatively propagated plantlets in some crassulaceae.
epiphyte: a plant growing on, but not parasitic on, another plant (often loosely applied to plants, such as orchids, that grow on vertical rock faces). cf. parasite, saprophyte.
equilateral: of stamens, with anthers regularly spaced around the style.
equitant: of leaves, folded in half along the midline so that the adaxial surface disappears, and overlapping the edges of a similarly folded leaf on the opposite side of the stem.
eremean: pertaining to regions of low, irregular rainfall.
erose: margin irregularly incised.
erose: of a margin, finely and irregularly eroded or toothed.
eusporangiate: of ferns, having sporangia with walls more than one cell thick. cf. leptosporangiate.
evergreen: bearing green leaves throughout the year.
excentric: to one side; off centre.
exine: the outer layer of the wall of a pollen grain or spore.
exocarp: the outer layer or skin of a pericarp.
exserted: protruding, e.g. of stamens with respect to a corolla tube.
exstipulate: without stipules.
extravaginal: of a shoot, arising from an axillary bud which breaks through the sheath of the subtending leaf.
extrorse: of anthers, opening away from the centre of the flower. cf. introrse.
facultative: of parasites, optional. cf. obligate.

falcate: sickle-shaped.
family: a group of one to many genera believed to be related phylogenetically, usually clearly separable from other such groups.
farinaceous: containing starch grains; mealy; resembling flour.
fascicle: a cluster, adj. fasciculate.
favulariate: of a surface, finely ribbed, the ribs separated by zig-zag furrows.
fenestrate: having openings or translucent areas ('windows').
fertilisation: the union of male and female gametes.
filament: the stalk of a stamen; a thread one or more cells thick; in blue-green Algae, a trichome enclosed in a mucilaginous sheath. cf. anther.
filiform: thread-like.
fimbriate: fringed along the margin.
fimbriate: of a margin, fringed with long slender hair-like processes (fimbriae).
fistular: hollow throughout its length.

flabellate: fan-shaped, with a wedge-shaped outline and sometimes conspicuously plaited or nerved. eg. the leaf of Gingko.
flaccid: limp; tending to wilt. cf. turgid.
flexuous (= flexuose): bent from side to side in a zig-zag form.
floccose: bearing tufts of soft hairs or wool which tend to rub off and adhere in small masses.
floral: belonging to or associated with a flower.
floret: a grass flower, together with the lemma and palea that enclose it (often applied to flowers in Cyperaceeae and Asteraceae).
flower: the sexual reproductive structure of the angiosperm, typically consisting of gynoecium, androecium and perianth and the axis bearing these parts.
foliaceous: leaf-like.

foliolate: relating to or composed of leaflets. 2 leaflets; bifoliolate, 3 leaflets; trifoliolate.
follicle: a dry, dehiscent fruit formed from one carpel and dehiscing along the line of fusion of its edges.
forb: a non-woody plant other than a grass, sedge, rush, etc. cf. herb.
foveate: pitted.
free-central: a placentation in which the ovules are borne on a free-standing central placenta within the ovary.
free: not fused or united (with other organs).
frond: a leaf especially of a fern, cycad or palm; a leaf-like portion of a non-vascular plant (e.g. a foliose alga).
fruit: the seed-bearing structure in an angiosperm, formed from the ovary after flowering.
frutescent: becoming shrub-like (woody).
fruticose: shrub-like.
fugacious: falling or withering away very early.
funicle (= funiculus): the stalk of an ovule.
fusiform: spindle-shaped, i.e. narrower at both ends than at the centre.
gamete: a cell or nucleus that fuses with another, of opposite sex, in sexual reproduction.
gametophyte: a plant, or phase of a plant's life cycle, that bears gametes.
gamopetalous (= sympetalous): with the petals united by their margins, at least at the base. cf. polypetalous.
gamophyllous: having the leaves or perianth segments united by their margins, at least at the base.
gamosepalous: having the sepals united by their margins, at least at the base.
gemma: an asexual reproductive body, bud-like and detaching itself from the parent plant.
geniculate: bent abruptly like a knee joint.
genotype: the total complement of hereditary factors (genes) acquired by an organism from its parents and available for transmission to its offspring. cf. phenotype.
genus: a group of species believed to be related phylogenetically and usually clearly separable from other such groups, or a single species without close relatives. pl. genera.
geophyte: a plant whose perennating buds are buried in the soil.
germination: the process in which a seed emerges from a period of dormancy.
glabrescent: becoming glabrous.
glabrous: without hairs.
gland: a structure, within or on the surface of a plant, with a secretory function.
glandular: bearing glands; functioning as a gland.
glaucous: blue-green in colour, with a whitish bloom (as in the juvenile leaves of many eucalypts).

globular (or globose): more or less ball shaped, spherical.
glochid: a barbed hair or bristle.
glomerule: a small compact cluster. adj. glomerulate.
glumaceous: glume-like, tending to be chaffy or membranous in texture.
glume: a bract in the inflorescence of a grass, sedge or similar plant.
grain: a fruit characteristic of grasses (= caryopsis); pollen grain, a microspore of a seed plant, or the partially developed gametophyte formed from it.
granulate: of a surface, granular.
gymnosperm: a seed plant with the ovules borne on the surface of a sporophyll. cf. angiosperm.
gynobasic: of a style, arising near the base of the gynoecium, e.g. between the lobes of the ovary.
gynodioecious: having bisexual flowers and female flowers, on separate plants.
gynoecium: the carpels of a flower collectively.
gynophore: a stalk bearing the gynoecium above the level of insertion of the other floral parts.
gynostemium: the upper part of an awn in grasses, when distinctly different in form from the lower part; (=column)
habit: the growth form of a plant, comprising its size, shape, texture and orientation.
habitat: the environment in which a plant lives.
half-inferior: of an ovary, partly below and partly above the level of attachment of the perianth and stamens.
halophyte: a plant adapted to living in highly saline habitats; a plant that accumulates high concentrations of salt in its tissues.
haploid: having a single set of chromosomes in the nucleus (i.e. having each gene locus represented only once).

hastate: spear-shaped; of a leaf blade, narrow and pointed but with two basal lobes spreading approximately at right angles.
haustorium: an absorbing organ through which a parasite obtains chemical substances from its host.
helicoid: coiled; of a cymose inflorescence, branching repeatedly on the same side.
helophytes: marsh plants.
hemiparasite: an organism which lives on and derives part of its nourishment from a different organism, and is partially self-supporting.
herb: any vascular plant that never produces a woody stem. cf. forb.
herbaceous: not woody; soft in texture.
hermaphrodite: bisexual, having both pistils and stamens in the same flower.
heteroblastic: having the adult parts of the plant (especially the leaves) distinctly different in form from the juvenile parts.
heterogamous: producing flowers of two or more kinds with respect to their fertile organs, e.g. male and female or bisexual and female. cf. homogamous.
heteromorphous (= heteromorphic): of two or more distinct forms.
heterosporous: producing separate male and female spores. cf. homosporous.
heterostylous: species in which flowers are similar except that the stigmas and anthers are held at different levels relative to each other, because style length differs between plants. cf. homostylous.
hilum: the scar on a seed coat (testa) at the place where it was attached to its stalk during development.
hirsute: bearing coarse, rough, longish hairs. cf. villous.
hispid: bearing stiff, bristly hairs.
hoary: covered with a greyish layer of very short, closely interwoven hairs.
holotype: a single specimen designated by the author of a plant (or animal) name, at the time of original publication, as that to which the name shall apply; the 'voucher specimen' of a name.
homogamous: having flowers of only one kind. cf. heterogamous.
homosporous: producing only one kind of spore in the sexual reproductive cycle, and hence one gametophyte which produces both male and female gametes. cf. heterosporous.
homostylous: species in which the flowers have stigmas and anthers held at the same level relative to each other on all plants. cf. heterostylous.
host: an organism on which a parasite lives and by which it is nourished (also applied, loosely, to a plant supporting an epiphyte).
hyalescent: becoming translucent.
hyaline: translucent, almost like clear glass.
hybrid: an offspring of genetically different parents (in a flora, usually applied where the parents are of different species).
hydrophytes: plants normally living with the vegetative parts submerged or floating in water, or only partially emergent.
hygroscopic: absorbing water and undergoing movements or changes brought about by changes in water content.
hypanthium: a cup or tube bearing floral parts above the base, and often above the top, of the ovary of a flower, e.g. in many Myrtales. cf. calyx tube.
hypocotyl: the part of the stem of an embryo or young seedling below the cotyledonary node.
hypodermis: a layer of cells below the epidermis.
hypogeal: of germination, having the cotyledon(s) remaining within the seed coat (testa). cf. epigeal.
hypogynous: arising below the level of insertion of the ovary (often applied, loosely, to a flower in which the sepals, petals and stamens are inserted below the ovary). cf. perigynous, epigynous.
imbibition: the absorption of water, seeds with high protein contents have a very high imbibing capacity, and will swell more from imbibing than seeds with more starch or cellulose.
imbricate: of perianth parts, having the edges overlapping in the bud. cf. valvate.

imparipinnate: having an uneven number of pinnae, by virtue of having one terminal pinna. cf. paripinnate.
incised: cut deeply, sharply and often irregularly (an intermediate condition between toothed and lobed).
included: enclosed, not protruding.
incrassate: thickened; of a pollen grain, with thickened margins around the apertures.
incumbent: of the orientation of an embryo, with the cotyledons lying face to face and folded downwards beside the radicle; of anthers, lying against the inner face of the filament.
incurved: bent or curved inwards or upwards; of leaf margins, curved towards the adaxial surface.
indefinite: variable in number; numerous; of stamens, more than twice as many as the petals or sepals; of an inflorescence, not terminating in a flower (i.e. having a continuing, terminal growing point).
indehiscent: not opening at maturity.
indeterminate (= monopodial): of growth, the condition in which the terminal bud persists and produces successive lateral branches.
indumentum: the epidermal appendages, e.g. hairs or scales, collectively.
induplicate: folded inwards so that the outer faces of the margins are in contact.
indurated: hardened.
indusium: tissue covering the sorus of a fern; the pollen-cup of Goodeniaceae.
inferior: of an ovary, at least partly below the level of attachment of the other floral parts. cf. superior.
inflexed: bent inwards. cf. deciduous.
inflexed: bent sharply upwards or forwards.
inflorescence: the group or arrangement in which flowers are borne on a plant.
infraspecific: of lower taxonomic rank than species.
infructescence: the grouping or arrangement in which fruits are borne on a plant.

infundibuliform: (or funnelform) funnel, trumpet or cone shaped. cf. turbinate
insectivorous: catching, and ostensibly feeding on, insects.
inserted (on): attached to; arising from.
integument: a covering; one of the outer layers of tissue of an ovule.
internode: the portion of a stem between the level of insertion of two successive leaves or leaf pairs (or branches of an inflorescence).
interpetiolar: of stipules, between the petioles of two opposite leaves. cf. intrapetiolar.
interrupted: of an inflorescence, having the flowers unevenly distributed along the axis, with conspicuous gaps.
intramarginal: situated inside but close to the margin, e.g. of a vein in a leaf.
intrapetiolar: between a petiole and the subtending stem. cf. interpetiolar.
introduced: not indigenous; not native to the area in which it now occurs. cf. adventive.
introrse: of anthers, dehiscing towards the centre of the flower. cf. extrorse.
involucre: a group of bracts enveloping a condensed inflorescence; a layer of tissue enveloping particular structures, e.g. an archegonium in Bryophyta, sporangia in Hymenophyllaceae.
involute: rolled inwards; of a leaf, with the margins rolled towards the adaxial surface.
irregular: see zygomorphic.
isolateral (=isobilateral): having structurally similar upper and lower surfaces.
isotype: a specimen which is, or is believed to be, a duplicate of the holotype, i.e. part of the same collection.
juvenile: of leaves, formed on a young plant and different in form from the adult leaves.
karyoevolution: evolutionary change in the chromosome set, expressed as changes in number and gross structure of the chromosomes; (more broadly), evolutionary relationships between taxa as indicated by karyotype differences.
karyotype: the gross morphology of the chromosome set, described in terms of number, length, centromere position, etc.
keel: a ridge like the keel of a boat; in particular, a boat-shaped structure formed by fusion of the two anterior petals of a flower in Fabaceae.
keeled: of leaves or bracts, folded and ridged along the midrib.
labellum: a lip; in orchidaceae, the distinctive median petal that serves as an alighting platform for pollinating insects.
labellum: in zingiberaceae and costaceae, a usually showy petaloid structure, staminodal in origin.
laciniate: slashed into narrow, pointed lobes.
lacrymiform: tear-shaped, i.e. more or less ovoid or obovoid.
lacuna: a gap or cavity.
lamella: a thin, plate-like layer; middle lamella, the layer between the walls of two adjacent cells.
lamina: the blade of a leaf.

lanceolate: of a leaf, about four times as long as it is broad, broadest in the lower half and tapering towards the tip.
latex: a viscous fluid exuded from the cut surfaces of the leaves and stems of certain plants.
latiseptate: with broad partitions. cf. angustiseptate.
latrorse: of anthers, opening laterally towards adjacent anthers.
latrorse: turned sideways, i.e. not or away from axis.
leaflet: one of the ultimate segments of a compound leaf.
lectotype: a specimen selected from among those cited with the original description to serve in place of a holotype where the holotype is missing or destroyed, or where no holotype was designated.
legume: a fruit characteristic of the families Mimosaceae, Caesalpiniaceae and Fabaceae, formed from one carpel and either dehiscent along both sides, or indehiscent; in particular, an edible crop species in the family Fabaceae.

lemma: the lower of two bracts enclosing a grass flower.
lenticel: a loosely-packed mass of cells in the bark of a woody plant, visible on the surface of a stem as a raised powdery spot, through which gaseous exchange occurs.
lenticular: shaped like a biconvex lens.
lepidote: covered with small, membranous scales.
leptocaul (= leptocladous):twiggy, with abundant, relatively slender branches.
leptosporangiate: of ferns, having sporangia with walls only one cell thick. cf. eusporangiate.
liane: a climbing or twining plant (usually applied to woody climbers).
lignified: converted into wood.
lignotuber: a woody swelling below or just above the ground, containing adventitious buds from which new shoots develop if the top of the plant is cut or burnt (common in the shrubby eucalypts and in many other fire-tolerant australian shrubs).
ligulate: bearing a ligule; strap-shaped.
ligule: a strap-shaped structure; a membranous, scarious or hairy appendage on the adaxial surface of a leaf, especially in gramineae, pteridophytes, palmae, zingiberaceae; the corolla limb in ray flowers of asteraceae.
limb: the upper, free, spreading portion of a corolla or perianth that is connate at the base.

linear: very narrow in relation to the length, and with the sides parallel.
lithophyte: a plant that grows on the surface of unweathered rock.

lobed: divided into lobes (rounded segments) separated from adjacent segments by sinuses which reach halfway or less to the middle of the organ. cf. cleft
lobulate: having small or indistinct lobes.
loculicidal: of the dehiscence of a fruit, along lines coinciding with the centres of loculi. cf. septicidal.
locule: usually refers to a chamber within an ovary (gynoecium or carpel of the flower and fruits). Depending on the number of locules in the ovary, carpels and fruits can be classified as uni-locular, bi-locular or multi-locular. The locules contain the ovules or seeds. The term may also refer to chambers within anthers containing pollen.
loculus: an enclosed compartment within an organ e.g. an ovary, an anther. pl. loculi.
lodicule: one of a pair of tiny scales in a grass floret, between the lemma and the fertile parts of the flower, which may be reduced perianth segments.
lomentum: a legume having distinct constrictions or lines of abscission between the seeds and breaking into one-seeded segments when mature.

lorate: of leaves, strap-shaped (moderately long with the two margins parallel).

lyrate: deeply lobed, with a large terminal lobe and smaller lateral ones.
macrospore: (=megaspore)
mallee: a growth form in eucalypts in which several stems arise from a lignotuber.
mallee: a growth habit in which several woody stems arise separately from a lignotuber (usually applied to shrubby eucalypts); a plant having the above growth habit.
mammillate: having small nipple-shaped projections.
marcescent: withering without falling off.
margin: edge or border - where two distinct things touch, or one ends.
marginal: occurring at or very close to the margin.
medifixed: attached by or at the middle, e.g. of anthers, attached to the filament at the middle of the connective.
megagametophyte: a plant body or cell lineage, formed by vegetative growth of the megaspore, that produces the female gametes of a heterosporous plant.
megasporangium: the larger of the two kinds of sporangia produced in the sexual life cycle of a heterosporous plant.
megaspore: the larger of the two kinds of spores produced in the sexual life cycle of a heterosporous plant, giving rise to the female gametophyte.
megasporophyll: a specialised leaf upon (or in the axil of) which one or more megasporangia are borne.
meiosis: the two-stage division of a diploid nucleus, occurring once in every sexual life cycle, in which gene recombination occurs and the number of chromosomes characteristic of the sporophyte plant is halved prior to producing gametes.
mericarp: one segment of a fruit that breaks at maturity into units derived from the individual carpels. cf. schizocarp.
meristem: growing regions of a plant in which cells that have retained their embryonic characteristics, or reverted to them secondarily, divide to produce new cells.
mery: the number of parts per whorl that characterises a particular flower (generally constant for the perianth whorls and less often for the whorl(s) of stamens also). adj. merous. cf. trimerous
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).
mesophyll: photosynthetic tissue of a green plant; of vegetation, characteristic of moist habitats and with soft, fairly large leaves predominating; a leaf whose area is within the approximate range 20<180 square cm.
microgametophyte: a plant body or cell lineage, formed by vegetative growth of the microspore, that produces the male gametes of a heterosporous plant.
micropyle: a small canal through the integument(s) of an ovule, persisting as a pore in the seed coat (testa).
microsporangium: the smaller of the two kinds of sporangia produced in the sexual life cycle of a heterosporous plant.
microspore: the smaller of the two kinds of spores produced in the sexual life cycle of a heterosporous plant, giving rise to the male gametophyte.
microsporophyll: a specialised leaf upon (or in the axil of) which one or more microsporangia are borne.
midrib: the central, and usually the most prominent, vein of a leaf or leaf-like organ.
monadelphous: of stamens, united by their filaments into one bundle.
moniliform: contracted at short regular intervals like a string of beads.
moniliform: of hairs, constricted between the cells like a string of beads; of fruits, constricted between the seeds.
monocarpic: flowering and fruiting only once during its life span.
monochasium: a cymose inflorescence with the branches arising singly. cf. dichasium.
monochlamydeous: of a flower, having only one whorl of perianth parts.
monoclinus: having male and female reproductive organs in the same flower.
monocotyledon: a flowering plant whose embryo has only one cotyledon (seed leaf). cf. dicotyledon.
monoecious: having the male and female reproductive structures in separate flowers but on the same plant. cf. dioecious.
monophyletic: derived from a single ancestral line. cf. polyphyletic.
monopodial: of growth, with a persistent terminal growing point producing many lateral organs successively; of a stem, growing in the above manner. cf. sympodial
monotypic: containing only one taxon of the next lower rank (e.g. applied to a family containing only one genus). cf. polytypic.
morphology: the form and structure of an organism or part of an organism; the study of form and structure.
motile: actively moving; self-propelled.
mucilage: slimy material exuded by certain plants or plant organs. adj. mucilaginous.
mucro: a sharp, abrupt terminal point. adj. mucronate.
muricate: rough on the surface due to minute, hard outgrowths of the epidermis.
muricate: rough on the surface; covered with short, hard tubers.
muriculate: rough with minute, short, hard points.
mycorrhiza: a symbiotic union between a fungus and a plant root.
naked: of sporangia, not covered by an indusium; of seeds, exposed on the surface of a sporophyll (not enclosed within an ovary); of flowers, without perianth; of protoplasts or gametes, not bounded by a cell wall.
nectary: a gland that secretes nectar. adj. nectariferous.
neotype: a specimen selected to serve in place of a holotype where none of the material to which the name was originally applied is known to have been preserved.
nerve: a vein.
neuter: sterile (e.g. of flowers in which neither the androecium nor the gynoecium is functional in reproduction).
nocturnal: of flowers, opening only at night.
node: the level (transverse plane) of a stem at which one or more leaves arise.
nomen conservandum: a name of a family or genus (or taxon intermediate between these two) that has been formally accepted as the correct name contrary to the usual principles of botanical nomenclature.
nomen illegitimum: a name which, at the time of its publication, was superfluous (because the taxon to which it was applied had already been named) or had already been applied to another plant.
nomen nudum: a name published without a diagnosis or description of the entity to which it applies, and without reference to either.
nomen rejiciendum: a name rejected in favour of a 'nomen conservandum'.
nucellus: the central tissue of an ovule, within which the megaspore mother cell is formed.
nucleus: the central or original part around which other parts are formed.
nut: a hard, dry, indehiscent fruit formed from two or more carpels but containing only one seed.
obconical: cone-shaped but attached at the narrower end.

obcordate: of a leaf blade, broad and notched at the tip; heart-shaped but attached at the pointed end. cf. cordate

oblanceolate: similar in shape to lanceolate but attached at the narrower end.
obligate: of parasites, unable to survive without the host. cf. facultative.

oblique: of a leaf or leaflet, larger on one side of the midrib than on the other, i.e. asymmetrical.
obloid: (a three-dimensional shape) with short, parallel sides and rounded ends, as if composed of two hemispheres linked together by a very short cylinder.

oblong: having the length greater than the width but not many times greater, and the sides parallel.

obovate: similar in shape to ovate but attached at the narrower end.
obsolescent: non-functional but not reduced to a rudiment.
obsolete: reduced to a rudiment, or completely lacking. cf. rudimentary, vestigial.
obsolete: vestigial (or rudimentary).

obtuse: blunt or rounded at the apex, the converging edges separated by an angle greater than 90 degrees.
ochrea: a sheath, formed from two stipules, encircling the node in polygonaceae.
ontogeny: the development of a single organism, i.e. the sequence of stages through which it passes during its lifetime.
operculum: a lid or cover becoming detached at maturity by abscission; in Eucalyptus (for example), a cap covering the bud and formed by fusion or cohesion of perianth parts.
opposite: of leaves, borne at the same level but on opposite sides of the stem; of floral parts, on the same radius (as). cf. alternate.

orbicular: circular or nearly so.
order: a taxonomic grouping of families believed to be closely related (sometimes a single family with no apparent close relatives).
orthotropous: of an ovule, erect so that the micropyle points away from the placenta.
osmophore: a specialised flower part that secretes odours, usually to attract pollinators.
ostiole: an opening or pore, e.g. (in moraceae) at the apex of a fig, or (in fungi and lichens) at the apex of a perithecium. adj. ostiolar, ostiolate.
ovary: the basal portion of a carpel or group of fused carpels, enclosing the ovule(s).

oval: similar to elliptic but more rounded at the base and tip.

ovate: shaped like a section through the long axis of an egg, and attached by the wider end. cf. ovoid.

ovoid: egg-shaped (in three dimensions). cf. ovate.
ovulate: with ovules.
ovule: a structure in a seed plant within which one or more megaspores are formed and which develops into a seed after fertilisation.
ovuliferous: bearing ovules (e.g. applied to scales in a megasporangiate cone in gymnosperms).
ovulode: sterile structures on the placenta.
pachycaul: thick-stemmed, not `twiggy' (unbranched, or the branches few and thick).
palea: in a grass floret, the upper one of the two bracts enclosing a flower.

palmate: of a leaf, divided into several leaflets which arise at the same point.

palmatifid: of a leaf, deeply divided into several lobes which arise (almost) at the same level. cf. pinnatifid.
palmatisect: a condition intermediate between palmate and palmatifid, with the green tissue of the lamina completely divided into several segments, but the segments not fully separated at the base.
palynology: the scientific study of pollen.
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.

paniculate: indeterminate and much branched.
pantoporate: of a pollen grain, with rounded apertures all over the surface.
papilla: a small, elongated protuberance on the surface of an organ, usually an extension of one epidermal cell. adj. papillose.
pappus: a tuft (or ring) of hairs or scales borne above the ovary and outside the corolla in asteraceae and possibly representing the calyx; a tuft of hairs on a fruit.
parasite: an organism living on or in a different organism and deriving nourishment from it. cf. saprophyte, epiphyte.
paratype: a specimen, other than the holotype, that was cited with the original publication of a name.
parenchyma: plant tissue consisting of mature, living cells that are relatively unspecialised in function.
parietal: attached to the margins of a structure; of placentation, having the ovules attached to placentas on the wall of the ovary.
paripinnate: having an even number of pinnae by virtue of having a pair in the terminal position. cf. imparipinnate.
parted: divided, almost to the base, into segments.cf. palmate, lobed

pectinate: a closely segmented pinnate form (usually leaf); like a comb.
pedate: of a palmate or palmately-lobed leaf, having the lateral segments divided again.
pedicel: the stalk of a flower. adj. pedicellate.
peduncle: the stalk of an inflorescence; in ferns, the stalk of a sporocarp. adj. pedunculate.
pellucid: transparent.
peltate: of a leaf, having the stalk attached to the lower surface of the blade, not to the margin (also applied, in the same sense, to other stalked structures).
pendulous: drooping; of ovules, attached at the top of the ovary and hanging downwards from an apical placenta.
penicillate: pencil-shaped; tufted like an artist's brush.
penninerved (= penniveined): having conspicuous lateral veins divergent from the midrib and lying approximately parallel to each other.
penniveined: with conspicuous lateral veins diverging from the midrib and lying approximately parallel to each other.
pentamerous: of a flower, having five parts in each floral whorl (not necessarily including the gynoecium).
pepo: literally, a pumpkin (latin); a fruit with firm skin, pulpy interior, many seeds and a single locule.
perennate: maintain a dormant, vegetative state throughout non-growing seasons.
perennial: a plant whose life span extends over more than two growing seasons.
perfoliate: of a sessile leaf or bract, having its base completely wrapped around the stem.
perianth: the calyx and corolla of a flower, especially where the two are similar.
pericarp: the wall of a fruit, developed from the ovary wall.
perigynous: of perianth segments and stamens, arising from a cup or tube (hypanthium) that is free from the ovary but extending above its base. cf. hypogynous, epigynous.
perisperm: nutritive tissue in an angiosperm seed, formed from the nucellus. cf. endosperm.
persistent: remaining attached to the plant beyond the expected time of falling (e.g. of sepals not falling after flowering).
petal: a member of the inner whorl of non-fertile parts surrounding the fertile organs of a flower, usually soft and coloured conspicuously.
petaloid: like a petal; soft in texture and coloured conspicuously.
petiole: the stalk portion of a leaf.
petiolule: the stalk portion of a leaflet.
phanerogam: (literally) a plant with conspicuous reproductive parts; a plant reproducing by seeds. cf. cryptogam.
phenotype: the physical characteristics of an organism; the outward expression of characteristics conferred on an organism by its genotype.
phloem: the tissue in the conducting system of a plant through which metabolites (products of chemical reactions in the plant) are transported.
phyllichnium: in casuarinaceae, the ridge of a branchlet aristate; pl. phyllichnia.
phylloclade: a very leaf-like, photosynthetic stem of a plant whose true leaves are much reduced. cf. cladophyll.

phyllode: a leaf whose blade is much reduced or absent, and whose petiole and rachis have assumed the functions of the whole leaf. cf. cladode.
phyllotaxy: the arrangement of leaves on a stem (when spiral, often expressed quantitatively as the fraction of the circumference of the stem that separates two successive leaves).
phylogeny: the evolutionary development of a plant group, i.e. its derivation from its ancestors and the relationship among its members. adj. phylogenetic.
phylum: a taxon of high rank, the major unit of classification. cf. division.
pilose: hairy, the hairs soft and clearly separated but not sparse.
pinna: a primary segment of the blade of a compound leaf.

pinnate: divided into pinnae; once-compound. cf. bipinnate, tripinnate.

pinnatifid: cut deeply into lobes that are spaced out along the axis (of the leaf). cf. palmatifid.

pinnatisect: dissected down to the midrib but having the segments confluent with it.
pinnule: a leaflet of a bipinnate leaf.
pistil: a free carpel or a group of fused carpels.
pistillode: a sterile pistil, often rudimentary.
pith: the central region of a stem, inside the vascular cylinder.
placenta: a region, within an ovary, to which ovules are attached.
placentation: the arrangement of placentas, and hence of ovules, within an ovary.

plicate: folded back and forth longitudinally like a fan.
plumose: like a feather; with fine hairs branching from a central axis.
plumule: the portion of an embryo that gives rise to the shoot system (as distinct from the root system) of a plant. cf. radicle.
pneumatophore: an air-vessel; an organ containing aerenchyma; in particular, a root of a mangrove plant, growing above the substratum.
pod: a leguminous fruit.
pollen: the microspores of seed plants; the powdery mass of microspores shed from anthers.
pollen-grain: see grain.
pollen-sac: see sac.
pollination: the transfer of pollen from the male organ, where it is formed, to the receptive region of a female organ, e.g. from anther to stigma.
pollinium: a cohering mass of pollen grains, transferred as a unit in pollination. pl. pollinia.
polygamodioecious: having bisexual and male flowers on some plants, and bisexual and female flowers on others.
polygamous: having bisexual and unisexual flowers on the same plant.
polymorphic: having more than two distinct morphological variants.
polypetalous: with free petals. cf. gamopetalous.
polyphyletic: composed of members that originated, independently, from more than one evolutionary line. cf. monophyletic.
polyploid: having more than two of the basic sets of chromosomes in the nucleus. cf. diploid, haploid
polytypic: containing more than one taxon of the next lower rank. cf. monotypic.
pome: a fleshy (false) fruit, formed from an inferior ovary, in which the receptacle or hypanthium has enlarged to enclose the true fruit.
porate: of a pollen grain, with rounded apertures only. cf. colporate.
posterior: of floral parts, on the side of the flower nearest to the axis. cf. anterior.
praemorse: appearing bitten off at the end.
prickle: a hard, pointed outgrowth from the surface of a plant, involving several layers of cells but not containing a vein.
probract: small, leaf-like structure at the base of an inflorescence in cucurbitaceae, usually arising opposite a tendril.
procumbent: trailing or spreading along the ground but not rooting at the nodes. cf. adventitious, runner, stolon.
proliferous: in conostylis, having erect or spreading, elongating stems which are capable of rooting at the nodes but rarely do so.
propagule: a structure with the capacity to give rise to a new plant, e.g. a seed, a spore, part of the vegetative body capable of independent growth if detached from the parent.
prophyll: a leaf formed at the base of a shoot, usually smaller than those formed subsequently.
prostrate: lying flat on the ground.
protandrous: having the male sex organs maturing before the female; of a flower, shedding the pollen before the stigma is receptive. cf. protogynous.
prothallus: a gametophyte body, especially in ferns and related plants.
protogynous: having the female sex organs maturing before the male; of a flower, shedding the pollen after the stigma has ceased to be receptive. cf. protandrous.
proximal: near to the point of origin or attachment. cf. distal.
pruinose: having a whitish, waxy, powdery bloom on the surface.
pseudo-: false; apparent but not genuine.
puberulous: covered with minute, soft, erect hairs.
pubescent: covered with short, soft, erect hairs.
pulvinus: a swelling at the base of the stalk of a leaf or leaflet, often glandular or responsive to touch.
punctate: marked with dots.
puncticulate: minutely dotted.
pungent: ending in a stiff, sharp point; having an acrid taste or smell.
pustulate: covered with small pustule- or blister-like elevations.
pyrene: the 'stone' (endocarp plus seed) of a succulent fruit. cf. berry, drupe.

pyxidium: a capsule ("box") whose lid opens to release the seeds.
quincuncial: of the arrangement of corolla lobes in a bud, a variant of imbricate aestivation.

raceme: an indeterminate inflorescence in which a main axis produces a series of flowers on lateral stalks, the oldest at the base and the youngest at the top. adj. racemose.
rachilla: the axis of a grass spikelet, above the glumes.
rachis: the axis of an inflorescence or a pinnate leaf; pl. rachises.
radical: of leaves, clustered at the base of the stem.
radicle: the portion of an embryo that gives rise to the root system of a plant. cf. plumule.
raphe: the part of the stalk of an anatropous ovule that is fused along the side of the ovule.
raphides: needle-like crystals that occur in bundles in the vacuoles of some plant cells.
ray: a zygomorphic flower in asteraceae; a radial band of cells traversing the conducting elements in woody stems.
ray: of a compound umbel, one of the first (lower) series of branches of the inflorescence axis.
receptacle: the axis of a flower (= torus); in ferns, an axis on which sporangia arise.
recurved: curved or curled downwards or backwards.
reflexed: bent sharply downwards or backwards.
regular: see actinomorphic.

reniform: kidney-shaped.
replum: a longitudinal partition in an ovary, formed between parietal placentas.
resupinate: twisted through 180°, e.g. as with the ovary of most Orchidaceae.
reticulate: forming a network.
retinaculum: a hook-like structure to which another structure is tethered; in Orchidaceae and Asclepiadaceae, the structure to which pollen masses are attached; in Acanthaceae, the persistent stalk of an ovule.
retrorse: directed backwards or downwards. cf. antrorse.
retuse: with a very blunt and slightly notched apex.
revolute: rolled downwards or backwards.
rhachilla: the secondary axis of a decompound leaf or inflorescence
rhachis: the axis of a compound leaf or inflorescence.
rhipidium: an inflorescence of cymose units, the lateral branches developed alternately in opposite directions.
rhizoid: a thread-like, unicellular absorbing structure, occurring in fern gametophytes and in some non-vascular plants.
rhizome: an underground stem, usually growing horizontally.
rhizophore: in selaginella, a leafless stem that produces roots.

rhomboid: quadangular, with the lateral angles obtuse.
root: a unit of the axial system of a plant which is usually underground, does not bear leaves, tends to grow downwards and is typically derived from the radicle of the embryo. see adventitious.
rootstock: a short, erect, swollen structure at the junction of the root and shoot systems of a plant.
rostellum: a beak-like upward extension of the stigma in Orchidaceae.
rosette: a circular arrangement of leaves. Dandelion, Agave
rosulate: clustered into a rosette.
rotate: circular and flattened, e.g. of a corolla with a very short tube and spreading lobes.
ruderal: growing in waste places.
rudimentary: poorly developed and not functional. cf. vestigial, obsolete.
rugose: deeply wrinkled.
rugulose: covered with minute wrinkles.
ruminate: mottled in appearance, e.g. of bark, or of the food reserves in a seed.

runcinate: deeply lobed and with the lobes slanted away from the apex.
runner: a slender, prostrate or trailing stem which produces roots and sometimes erect shoots at its nodes.
sac: a pouch or cavity; pollen-sac.
saccate: pouched.

sagittate: shaped like an arrow-head.

samara: a dry, indehiscent fruit with its wall expanded into a wing. (A winged achene.)
saprophyte: an organism deriving its nourishment from dead organic matter and usually lacking chlorophyll. cf. epiphyte, parasite.
scabrid (= scabrous): rough to the touch.
scabridulous: slightly rough; diminutive of scabrous.
scalariform: having a ladder-like pattern.
scale: a reduced or rudimentary leaf, e.g. surrounding a dormant bud; a thin flap of tissue, e.g. on the ventral surface of a liverwort thallus and at the base of a stamen in Simaroubaceae.
scandent: climbing.
scape: the stem-like, flowering stalk of a plant with radical leaves.
scarious: dry and membranous.
schizocarp: a dry fruit formed from more than one carpel but breaking apart into 1 -carpel units when ripe. cf. mericarp.
sclerenchyma: mechanical tissue with heavily thickened cell walls.
scleromorph: a plant whose leaves (or stems, if leafless) are hard in texture, usually having thick cuticle and containing many fibres. cf. xeromorph.
sclerophyllous: with leaves stiffened by sclerenchyma.
scorpioid: of a cymose inflorescence, branching alternately on one side and then the other. cf. helicoid.
scribble: irregular lines on the bark of some eucalypts, being the old tunnels burrowed by moth larvae between bark layers and exposed when the outer layer falls.
secund: with all the parts grouped on one side or turned to one side (applied especially to inflorescences).
seed: a propagating organ formed in the sexual reproductive cycle of gymnosperms and angiosperm, consisting of a protective coat (testa) enclosing an embryo and food reserves.
segment: a part or sub-division of a divided organ; one of a group of similar organs named collectively, e.g. one petal = a segment of a corolla.
sepal: a member of the (usually green) outer whorl of non-fertile parts surrounding the fertile organs of a flower.
sepaloid: looking like sepals, e.g. of bracts, usually green and arranged in a ring beneath a flower.
septate: divided internally by partitions.
septicidal: of the dehiscence of a fruit, along lines coinciding with the partitions between loculi. cf. loculicidal.
septifragal: of the dehiscence of a fruit, when the valves or backs of the carpels break away leaving the septa intact.
septum: a partition. pl. septa.
seriate: in rows or whorls.
sericeous: silky; covered with silky hairs.
serrate: toothed, with asymmetrical teeth pointing forward.
serrulate: finely serrate.
sessile: without a stalk (when applied to a stigma, indicates that the style is absent, the stigma being 'sessile' on the ovary).
seta: a bristle or stiff hair; in bryophyta, the stalk portion of a sporophyte plant body; terminal seta.
setose: bristly.
shrub: a woody plant less than 5 metres high, either without a distinct main axis, or with branches persisting on the main axis almost to its base.
siliceous: containing silica.
silicula: a short siliqua, not more than twice as long as its width.
siliqua: a dry, dehiscent fruit formed from a superior ovary of two carpels, with two parietal placentas and divided into two loculi by a false septum between the placentas.
simple: undivided; of a leaf, not divided into leaflets; of a hair or an inflorescence, not branched.
sinuate: with deep, wave-like depressions along the margin. cf. undulate.
sinus: a notch or depression in the margin of an organ.
solitary: of flowers, borne singly, not grouped in an inflorescence.
sorus: in ferns, a discrete group of sporangia. pl. sori.

spadix: a spicate inflorescence with a stout, often succulent axis.
spathaceous: like a spathe; with a spathe.

spathe: a large bract ensheathing an inflorescence.
spathella: a closed membranous sac which envelopes the immature flower in some podostemaceae, rupturing irregularly as the pedicel elongates at anthesis.

spathulate (= spatulate): spoon-shaped; broad at the tip and narrowed towards the base.
species: a taxon comprising individuals, or populations of individuals, capable of interbreeding to produce fertile offspring;
species: the largest group of individuals between which there are no distinguishable, consistent differences in form or reproductive mechanisms.

spike: an unbranched, indeterminate inflorescence in which the flowers are without stalks. adj. spicate.
spikelet: a unit of the inflorescence in grasses, sedges and some other monocotyledons, consisting of one to many flowers and associated glumes.
spine: a stiff, sharp-pointed structure, formed by modification of a plant organ, e.g. a lateral branch or a stipule.
spinescent: ending in a spine; modified to form a spine.
spinose: bearing spines.
spiral: of leaves or floral organs, borne at different levels on the axis, in an ascending spiral, eg Echium wildpretii. cf. cyclic.
sporangiophore: the stalk of a sporangium.
sporangium: a structure within which spores are formed. pl. sporangia.
spore: a simple propagule, produced either sexually or asexually, and consisting of one or a few cells.
sporocarp: a fruiting body containing sporangia.
sporogenous: of cells or tissues, in which spores are formed.
sporophyll: a specialised leaf-like organ on which one or more sporangia are borne.
sporophyte: a plant, or phase of a life cycle, that bears the spores formed during the sexual reproductive cycle.
spur: a tubular pouch at the base of a perianth part, often containing nectar.
stamen: one of the male organs of a flower, consisting typically of a stalk (filament) and a pollen-bearing portion (anther). adj. staminate.
staminode: a sterile stamen, often rudimentary.
staminophore: a band of tissue around the apex of the hypanthium in a eucalypt flower on which the stamens are inserted.
standard: the posterior petal in the flower in Fabaceae.
stellate: star-shaped; consisting of star-shaped cells.
stem: the main axis or a branch of the main axial system of a plant, developed from the plumule of the embryo and typically bearing leaves.
stigma: the pollen-receptive surface of a carpel or group of fused carpels, usually sticky.
stipe: a small stalk; in ferns, the petiole of a frond; in algae, the cylindrical basal portion of a thallus.
stipitate: stalked; borne on a stipe; of an ovary, borne on a gynophore.
stipule: one of a pair of appendages at the bases of leaves in many dicotyledons.
stolon: a prostrate or trailing stem that produces roots at the nodes.
stoloniferous: having stolons; trailing over the soil surface and rooting at the nodes.
stoma: a pore; a pore in the epidermis of a leaf or other aerial organ, providing access for gaseous exchange between the tissues and the atmosphere. pl. stomata.
stomium: a region of dehiscence, e.g. of an anther in flowering plants or of a capsule in mosses. pl. stomia.
stramineous: straw coloured.
striate: striped with parallel longitudinal lines or ridges.
strigose: with sharp, stiff hairs which are slanting rather than erect.

strobilus: a 'cone' consisting of sporophylls borne close together on an axis.
strophiole: see caruncle
struma: a cushion-like swelling, e.g. at the apex of staminal filaments in dianella.
style: an elongated part of a carpel, or group of fused carpels, between the ovary and the stigma.
subulate: narrow and tapering gradually to a fine point.
sulcate: grooved; furrowed.
superior: of an ovary, borne above the level of attachment of the other floral parts, or above the base of a cup (hypanthium) that is free from the ovary and bears the perianth segments and stamens. cf. inferior.
suture: a line of junction between two fused organs; a line of dehiscence.
subsessile: nearly sessile; almost without a stalk.
syconium: a multiple fruit with a hollow centre, e.g. in ficus (fig).
sympatric: of two or more species, having coincident or ovarlapping ranges of distribution. cf. allopatric.
sympetalous: = gamopetalous
sympodial: of growth, without a single, persistent growing point; changing direction by frequent replacement of the growing apex by a lateral growing point below it; of a stem, growing in the above manner. cf. monopodial.
synandrium: an androecium with the anthers of the stamens cohering. cf. syngenesious.
synangium: of fruit, several fruits united in a single structure.
syncarp: a structure consisting of several united fruits, usually fleshy. cf. aggregate fruit.
syncarpous: of a flower, having two or more carpels, all fused together.
syngenesious: of the stamens of one flower, fused together by the anthers e.g. in asteraceae. cf. synandrium.
syntepalum: in musaceae, a unilaterally split tube formed by the coherence of 3 sepals and 2 anterior petals in flowers of some species.
syntype: one of two or more specimens cited by the author at the time of publication of a name for which no holotype was designated.
taproot: the main, descending root of a plant that has a single, dominant root axis.
taxon: a group or category, at any level, in a system for classifying plants or animals.
tendril: a slender climbing organ formed by modification of a part of a plant, e.g. a stem, a leaf or leaflet, a stipule.
tenuiexenous: of a pollen grain, with a thin exine.
tepal: a perianth segment in a flower in which all the perianth segments are similar in appearance.
terete: cylindrical or nearly so; circular in cross-section.
terminal: at the apex or distal end.
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 the habitat of a plant, on land as opposed to in water, or on the ground as opposed to on another plant.
testa: a seed coat.
tetrad: a group of four; four pollen grains remaining fused together at maturity, e.g. in Ericaceae, Epacridaceae.
tetradynamous: of an androecium, consisting of four stamens of the same length and two of a different length.
tetramerous: of a flower, having four segments in each perianth whorl, and usually in each whorl of stamens also.
thallus: the vegetative body of a plant that is not differentiated into organs such as stems and leaves, e.g. algae, the gametophytes of many liverworts, and Lemnaceae.
thorn: a modified plant organ, especially a stem, that is stiffened and terminates in a pungent point.
throat: of a corolla tube, the top, where the tube joins the lobes.

thyrse: a branched inflorescence in which the main axis is indeterminate and the lateral branches determinate in their growth. Thyrses' flowers are arranged along the main axis in cymes 
tomentum: a covering of dense, matted, woolly hairs. adj. tomentose.
torus: see receptacle.
trabecula: a transverse partition dividing or partly dividing a cavity.
tree: a woody plant at least 5 metres high, with a main axis the lower part of which is usually unbranched.
trichome: an unbranched epidermal outgrowth, e.g. a hair, a papilla; in blue-green algae, a single row of cells in a filamentous colony.
trichotomous: branching almost equally into three parts.
trifid: deeply divided into three parts.
trifoliate: having three leaves.

trifoliolate: of a leaf, having three leaflets.
trigonous: triangular in cross-section and obtusely-angled. cf. triquetrous.
trimerous: of a flower, having three segments in each perianth whorl and usually in each whorl of stamens also.
tripinnate: of leaves, thrice pinnately divided.
triplicate: folded three times.
triquetrous: triangular in cross-section and acutely-angled; with three distinct longitudinal ridges. cf. trigonous.
tristichous: arranged in three rows on a stem, each row in the same plane.
tristylous: heterostylous species having three style lengths (short, mid, long), the flowers of any one plant having styles of the same length.
truncate: with an abruptly transverse end, as if cut off.
tuber: a storage organ formed by swelling of an underground stem or the distal end of a root.
tubercle: a small wart-like outgrowth.
tuberculate: covered with tubercles.
tuberous: swollen; of roots, tuber-like.
tumid: swollen; inflated.
tunic: thin membranous or fibrous outer layers of a bulb or corm.

turbinate: top-shaped, obconical.
turgid: swollen due to high water content. cf. flaccid.
type: a designated representative of a plant name.

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.
uncinate: terminating in a hooked point.
undulate: wavy, i.e. not flat. cf. sinuate.
unifoliate: having one leaf.
unifoliolate: of a leaf, basically compound, but reduced to only one leaflet.
unilateral: of stamens, with anthers grouped to one side of the style.
unilocular: of an ovary, anther or fruit, having only one internal cavity.
unisexual: bearing only male or only female reproductive organs.
united: fused together.
urceolate: urn-shaped.

utricle: a small bladder; a membranous bladder-like sac enclosing an ovary or fruit.
valvate: of sepals or petals in a bud, meeting edge to edge, not overlapping. cf. imbricate.
valve: a portion of an organ that has fragmented; of a capsule, the teeth-like portions into which the dehiscing part of the pericarp splits at maturity.
vascular: specialised for conduction of fluids; vascular plants.
vein: a strand of vascular tissue.
velamen: a water-retaining outer layer of the aerial roots of some epiphytes, especially orchids.
velum: a membranous covering; a veil.
venation: the arrangement of veins in a leaf.
ventral: of a lateral organ, facing towards the subtending axis; of a thallus, facing towards the substratum. cf. dorsal.
vernation: the arrangement of unexpanded leaves in a bud. cf. aestivation.
verrucose: covered with wart-like outgrowths.
verrucose: warted.
verruculose: covered with closely spaced, minute wart-like outgrowths.
versatile: of anthers, swinging freely about the point of attachment to the filament, which is approximately central.
verticillate: arranged in one or more whorls.
vesicle: a bladder-like sac or cavity filled with gas or liquid.
vessel: a capillary tube formed from a series of open-ended cells in the water -conducting tissue of a plant.
vestigial: reduced from the ancestral condition and no longer functional. cf. obsolete, rudimentary.
villous: shaggy with long, weak hairs. cf. hirsute.
viscid: of a surface, sticky; coated with a thick, syrupy secretion.
viscous: of a liquid, not pouring freely; having the consistency of syrup or honey.
viviparous: of seeds or fruits, germinating before being shed from the parent plant.
whorl: a ring of leaves, bracts or floral parts borne at the same level on an axis.
wing: a membranous expansion of a fruit or seed, which aids dispersal; a thin flange of tissue extended beyond the normal outline of a stem or petiole; a lateral petal of a flower in Fabaceae.
xeromorph: a plant having structural features usually associated with plants of arid habitats (such as hard or succulent leaves) but not necessarily drought-tolerant. cf. scleromorph, xerophyte.
xerophyte: a drought-tolerant plant. cf. xeromorph.
xylem: the tissue, in a vascular plant, that conducts water and mineral salts from the roots to the leaves.
zygomorphic: of a flower or calyx or corolla, symmetrical about one plane only, usually the plane that bisects the flower vertically. cf. actinomorphic.
zygote: A zygote is a single diploid cell produced by the combination of two haploid cells - a female ovule and a male sperm. The zygote contains DNA originating from both mother and father with all the genetic information necessary to form a new individual.
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