Glossary A - B

abaxial: 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 (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.

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 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.

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: having bisexual flowers and male flowers, on separate plants.

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 whose life span ends within one year after germination.

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, end; especially of leaves.

apetalous: without petals.

apical: of a placenta, at the top of the ovary.

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 against but not united with.

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.

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.

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.

attenuate: tapering gradually.

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.

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.

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.