Australian Biological Resources Study
Compiled by A.McCusker
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). cf. diploid, polyploid.
hastate: spear-shaped; of a leaf blade, narrow and pointed but with two basal lobes spreading approximately at right angles. > image <
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. > image <
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. > image <