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: see sympetalous.

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: a bud or bud-like organ capable of reproducing the plant. pl. gemmae.

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; the major taxonomic rank between species and family. pl. genera.

geophyte: a plant whose perennating buds are buried in the soil.

gibbous: usually of a calyx or corolla, with a large hump or pouch-like swelling.

glabrate: glabrous, but obviously having previously had an indumentum.

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 Eucalyptus species).

globose: nearly 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.

guard cells: the two cells that open and close the stomata to allow gas exchange.

gymnosperm: a seed-bearing 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. cf. gynomonoecious.

gynoecium: the carpels of a flower collectively.

gynomonoecious: having bisexual and female flowers on the same plant cf. gynodioecious.

gynophore: a stalk bearing the gynoecium above the level of insertion of the other floral parts.

gynostegial corona: in Asclepiadaceae, collective term for the staminal and interstaminal coronas, both of which are associated with the gynostegium. See staminal corona, interstaminal corona.

gynostegium: in Asclepiadaceae, a structure formed by the fusion of the stamens. cf. column.

gynostemium: inOrchidaceae, a structure formed by the fusion of the androecium and the gynoecium. cf. column.

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habit: the growth form of a plant, comprising its size, shape, texture and orientation.

habitat: the environment in which a plant lives.

hair: an elongate single-celled or multi-celled outgrowth from the epidermis, without vascular tissue.

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). cf. diploid, polyploid.

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.

head: see capitulum.

helicoid: coiled; of a cymose inflorescence, branching repeatedly on the same side. cf. scorpioid.

hemiparasite: an organism which lives on and derives part of its nourishment from a different organism, and is partially self-supporting. cf. parasite.

herb: any vascular plant that never produces a woody stem. cf. forb.

herbaceous: not woody; soft in texture.

hermaphrodite: = bisexual.

hesperidium: a fleshy indehiscent fruit derived from a single pistil, with an outer leathery rind and septate interior, e.g. Citrus.

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.

heteromorphic (= heteromorphous): of two or more distinct forms.

heterosporous: producing two kinds of spores (male and female, or microspores and megaspores). 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 at the place where it was attached to its stalk during development.

hirsute: bearing coarse, rough, relatively long hairs. cf. villous.

hispid: bearing stiff, bristly hairs.

hispidulous: minutely hispid.

hoary: covered with a greyish layer of very short, closely interwoven hairs.

holotype: a single specimen or illustration designated by the author of a plant (or animal) name, at the time of original publication, which fixes the application of the name; the 'voucher specimen' of a name. cf. isotype, type.

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).

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 clearly differentiated layer of cells below the epidermis.

hypogeal: of germination, having the cotyledon(s) remaining within the seed coat. cf. epigeal.

hypogynous: of perianth segments and stamens, 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. epigynous, perigynous.

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Last updated on 13 May 1999.

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