Herissantia Medik.

Scientific Description

Family Malvaceae.

Tribe Malveae.

Habit and leaf form. Spreading herbs (with an indumentum of stellate hairs or simple hairs). Plants unarmed. Annual, or perennial. Mesophytic. Leaves alternate; spiral; petiolate; non-sheathing; simple. Leaf blades dorsiventral; entire; ovate; palmately veined; cordate. Mature leaf blades adaxially pubescent; abaxially pubescent. Leaves with stipules (stipules subulate). Leaf blade margins crenate. Leaf anatomy. Hairs present; complex hairs present. Complex hairs stellate. Extra-floral nectaries absent.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous.

Inflorescence and flower features. Flowers solitary; axillary; pedicellate (pedicels articulate); small; regular; 5 merous; tetracyclic. Hypogynous disk absent. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous; lobed; lobulate (deeply 5-lobed); hairy; valvate; exceeded by the corolla; regular. Calyx lobes triangular. Epicalyx absent. Corolla present; 5; 1 -whorled; polypetalous (adnate to the base of the staminal column); white, or yellow. Petals obovate. Androecium present. Androecial members indefinite in number. Androecium 50–100 (i.e. ‘many’). Androecial members adnate; all equal; coherent (connate; the filaments fused in a column surrounding the style); 1 - adelphous (the tube attached to the petals); 1 -whorled. Androecium exclusively of fertile stamens (or rather, half-stamens, each having only a half anther). Stamens 50–100. Anthers dehiscing via longitudinal slits; introrse; unilocular. Gynoecium 8–15 carpelled (in a single whorl). The pistil 8–15 celled. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary plurilocular; 8–15 locular. Gynoecium stylate. Styles 1; more than 4-branched (8–15-branched, i.e. as many as the carpels); apical. Stigmas 8–15. Placentation axile. Ovules 2–10 per locule (i.e. 2-several).

Fruit and seed features. Fruit 5–6 mm long; non-fleshy; hairy, or not hairy; a schizocarp (separating septicidally into 2-valved mericarps leaving a persistent central axis). Mericarps 8–15. Dispersal unit the mericarp (reniform in outline, laterally compressed, inflated, membranous-chartaceous, the outer edge awned). Seeds 2 or more per mericarp. Seeds conspicuously hairy.

Geography, cytology, number of species. World distribution: America and Australia. Adventive. Australian states and territories: Western Australia and Northern Territory. Northern Botanical Province. A genus of c. 5 species; 1 species in Western Australia; 0 endemic to Western Australia.

Additional comments. Often placed in the genus Abutilon. Etymology: commemorates Louis Antoine Prospere Herissant, 1745–1769, a French physician, naturalist and poet.