D

deciduous: falling seasonally, e.g. of the leaves or bark of some trees. cf. evergreen.

declinate: angled downwards or forwards. cf. decurved.

decompound: more than once compound.

decumbent: spreading horizontally but then growing upwards.

decurrent: extending downwards beyond the point of insertion, e.g. of a leaf lamina extending downwards to form a flange along the petiole.

decurved: angled downwards and curved or curled. cf. declinate.

decussate: in opposite 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 abruptly downwards. cf. inflexed.

dehiscent: breaking open at maturity to release the contents.

deltoid (= deltate): triangular with the sides of about equal length.

dendritic: of a trichome, with branches arising along the main axis, i.e. tree-like.

dendroid: tree-like in form but not in size. cf. arborescent.

dentate: toothed.

denticle: a small tooth; in Coprosma (Rubiaceae), thick papillate tubercles on the margin of the interpetiolar stipules.

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.

dextrorse: turned towards the right. cf. sinistrorse.

diadelphous: having the stamens united into two groups, or all but one united in a group and one free. cf. monadelphous.

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. cf. monochlamydeous.

dichotomous: forking into two equal branches resulting from division of the growing point.

diclinous: having the stamens and the carpels in separate flowers. cf. monoclinous.

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 an androecium, consisting of four stamens, two being distinctly longer than the other two. cf. tetradynamous.

digitate: branching from the axis or stalk like the fingers of a hand.

dimidiate: appearing to be halved, as when half an organ is so much smaller than the other that it seems absent.

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.

disc floret: an actinomorphic flower in Asteraceae. cf. ray floret.

discolorous: of different colours; of leaves, having the two surfaces different in colour; variegated. 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. Alternative name for phylum.

domatia: small structures on the lower surface of a leaf in some woody dicotyledons, located in the axils of the primary veins and usually consisting of depressions partly enclosed by leaf tissue or hairs. 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. cf. isobilateral.

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.

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Last updated on 13 May 1999.

Australian Biological Resources Study