caducous: falling off early.
caespitose: growing in tufts.
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 on the axis of the spikelet of some grasses. adj. callose; pl. calli.
calycine: belonging to the calyx; with a well-developed calyx.
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), a cap formed by fusion or cohesion of perianth parts and covering the stamens and carpels in the bud.
calyx tube: a tube formed by fusion or cohesion of sepals. cf. hypanthium.
calyx: the sepals of one flower collectively.
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.
canescent: more or less grey-pubescent, hoary.
canopy: the branches and foliage of a tree. cf. bole.
capillary: of hairs etc., very slender.
capitate: of an inflorescence, with the flowers unstalked and aggregated into a dense cluster; of a stigma, globose, like the head of a pin.
capitellate: shaped like, or aggregated into, a very small head.
capitulum (= head): a dense cluster of sessile flowers. adj. capitate.
capsule: a dry fruit formed from two or more united carpels and dehiscing at maturity to release the seeds.
carpel: an organ (generally believed to be a modified foliar unit) 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 central axis between the carpels, arising from the receptacle and often persistent, e.g. after mericarps are shed.
caruncle (= strophiole): an outgrowth of a seed coat, near the hilum.
caryopsis: a dry, indehiscent, one-seeded fruit in which the seed coat is closely fused to the fruit wall (characteristic of grasses).
cataphyll: a scale leaf, often associated with a vegetative propagating organ such as a rhizome or perennating bud.
catkin: a 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: the thread-like part of a pollinarium that connects the corpusculum with the pollinia, characteristic of Orchidaceae and Asclepiadaceae.
cauliflorous: of plants, with flowers (and fruits) borne on a well-developed trunk or major branch. cf. cauline, ramiflorous.
cauline: of leaves, borne on an aerial stem; of flowers or fruits, borne on old wood. cf. cauliflorous.
cell: the basic unit of plant structure consisting, at least when young, of a protoplast surrounded by a wall.
centrifugal: directed, or developing, from the centre or axis outwards.
centripetal: directed, or developing, from the outside towards the centre or axis.
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.
chasmogamous: pollinated when the flower is open. cf. cleistogamous.
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 gametes, spores etc., minute hair-like protoplasmic protrusions whose movement confers motility on the cell; in vascular plants, hairs more or less confined to the margins of an organ. sing. cilium; adj. ciliate.
ciliolate: minutely ciliate.
cincinnus: a monochasial, cymose inflorescence with flowers arising alternately from one side of an axis then the other.
cinereous: ash-grey, as of wood ash.
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.
clathrate: latticed or pierced with apertures like a trellis.
claw: a narrow, stalk-like basal portion of a petal, sepal or bract. cf. limb.
cleistogamous: self-pollinated and setting fertile seed but the flowers never opening. cf. chasmogamous.
clone: a set of organisms produced from one parent by vegetative reproduction.
coccus: a one-carpel unit of a schizocarp or 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.
colleter: a group or tuft of mucilaginous secretory hairs, often found near the base of the leaf lamina and on the calyx in Apocynaceae and Asclepiadaceae.
colliculate: covered with small, rounded or hillock-like elevations (pl. n. colliculae).
colpate: of a pollen grain, having elongate apertures called colpi (sing. colpus). cf. colporate, porate.
colporate: of a pollen grain, having apertures with pores within colpi. cf. colpate, porate.
columella: a little column; the central, persistent axis of a schizocarpic fruit; the axis of a cone or cone-like fruit.
column: the lower part of an awn in grasses, when distinctly different in form from the upper part; a structure in Orchidaceae (= gynostemium) and Stylidiaceae, extending above the ovary of a flower and incorporating stigma, style and stamens; in Asclepiadaceae a structure formed by the fusion of the stamens only (= gynostegium).
coma: a tuft, especially of hairs on a seed. 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; of leaves, the same colour on both surfaces. cf. discolorous.
conduplicate: folded together, with the fold-line along the long axis, e.g. of cotyledons in a seed.
cone: in gymnosperms and club-mosses, a group of sporophylls arranged compactly on a central axis; (loosely) in Casuarinaceae, a woody multiple fruit incorporating the bracts and bracteoles associated with the flowers; (loosely) in Petrophile and other Proteaceae the semi-woody multiple fruit made up of nutlets in the axils of closely imbricate floral bracts which become woody.
conflorescence: a compound inflorescence consisting of two or more unit inflorescences, in which the main axis does not end in a flower but the axes of the branches do so.
connate: fused to another organ (or other organs) of the same kind. cf. adnate.
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 (in two dimensions).
cordiform: shaped like a heart (in three dimensions).
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.
corolline corona: fleshy ridges or outgrowths of tissue attached to the corolla tube, usually in the lobe sinuses.
corona: a ring of tissue arising from the corolla, perianth or filaments of a flower and standing between the perianth lobes and the stamens.
corpusculum: the central part of a pollinarium, characteristic of Orchidaceae and Asclepiadaceae.
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.
costa: a rib; a midrib or midvein (when it is the only vein).
costule: the midvein of a pinnule.
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.
crownshaft: in palms, a conspicuous cylinder formed by the tubular base of leaf sheaths at the top of a stem.
cryptogam: (literally) a plant whose sexual reproductive parts are not conspicuous; a plant that produces spores, not seeds, in its sexual reproductive cycle; among vascular plants, ferns and fern allies. cf. phanerogam.
cucullate: hooded; hood-shaped.
culm: an aerial stem; in grasses, sedges, rushes, etc., the stem bearing the inflorescence.
cupule: a small cup.
cupuliform: nearly hemispherical, shaped like a cupola (dome).
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.
cyathium: an inflorescence of unisexual flowers surrounded by a cup of involucral bracts, as in Euphorbia.
cyclic: of floral organs, several borne at the same level on the axis; whorled. cf. spiral, whorl.
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. adj. cymose. cf. raceme.
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.
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Last updated on 13 May 1999.