Habit and leaf form. Herbs; evergreen; bearing essential oils; not resinous. Plants unarmed. Perennial. Leaves cauline. Plants with neither basal nor terminal concentrations of leaves. Young stems tetragonal. Stem internodes solid, or hollow. To 0.8–2 m high. Self supporting, or climbing. Leaves small; opposite; not decussate; not decurrent on the stems; ‘herbaceous’; not imbricate; petiolate; aromatic, or foetid, or without marked odour; simple; epulvinate. Leaf blades entire; flat; narrowly elliptic, or triangular (to narrowly ovate); pinnately veined; cross-venulate; cordate to cuneate at the base, or rounded at the base. Mature leaf blades pilose, or woolly (sometimes). Leaves without stipules. Leaf blade margins crenate, or serrate; flat. Leaves without a persistent basal meristem. Leaf anatomy. Hairs present (hairs antrorse to subpatent); glandular hairs present; complex hairs absent. Branched hairs present. Urticating hairs absent. Stem anatomy. Secondary thickening developing from a conventional cambial ring.
Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous, or ornithophilous; via hymenoptera, or via lepidoptera, or via diptera.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’. Inflorescence few-flowered to many-flowered. Flowers in cymes, in panicles, and in verticils. The terminal inflorescence unit cymose. Inflorescences axillary; thyrsoidal with the monchasial units of the inflorescence arranged in whorls. Flowers sessile; bracteate; small; very irregular; zygomorphic. The floral asymmetry involving the perianth and involving the androecium. Flowers cyclic; tetracyclic. Floral receptacle developing a gynophore, or with neither androphore nor gynophore. Free hypanthium absent. Hypogynous disk present, or absent. Perianth with distinct calyx and corolla; 4–10; 2 -whorled; isomerous, or anisomerous (or only dubiously interpretable). Calyx present; 5; 1 -whorled; gamosepalous; blunt-lobed, or toothed; prominently 10 veined; imbricate, or open in bud; exceeded by the corolla; tubular campanulate (conic basally, expanded distally); regular; non-fleshy; persistent; with the median member posterior. Calyx lobes triangular. Corolla present; disguisedly 5; 1 -whorled; gamopetalous; imbricate; bilabiate (the abaxial lip comprising the lateral and abaxial lobes, the abaxial lobe itself distally 2-lobed and much longer than the lateral lobes; the adaxial lobe erect); with contrasting markings; purple (to purple-mauve). Corolla members entire. Androecium present. Fertile stamens present. Androecial members definite in number. Androecium 4. Androecial members adnate; markedly unequal; free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 4; becoming exserted; didynamous; all more or less similar in shape; reduced in number relative to the adjacent perianth; fertile stamens representing the posterior-lateral pair and the anterior-lateral pair; oppositisepalous; all alternating with the corolla members. Filaments hairy (puberulent or pubescent). Anthers connivent, or separate from one another; dorsifixed; versatile, or non-versatile; dehiscing via longitudinal slits; introrse; unilocular and bilocular (abaxial pair 2-celled, adaxial pair 1-celled); tetrasporangiate; unappendaged. Pollen shed as single grains. Fertile gynoecium present. Gynoecium 2 carpelled. The pistil 4 celled. Carpels reduced in number relative to the perianth. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary plurilocular; 2 locular, or 4 locular. Locules secondarily divided by ‘false septa’. Gynoecium median; stylate. Styles 1; from a depression at the top of the ovary; ‘gynobasic’. Stigmas 2, or 1; 2 - lobed (unequally divided). Placentation basal. Ovules 2 per locule (per carpel), or 1 per locule (per locellus); ascending; apotropous; non-arillate; anatropous, or hemianatropous.
Fruit and seed features. Fruit non-fleshy; a schizocarp. Mericarps 4; comprising nutlets. Seeds non-endospermic; small. Embryo well differentiated. Cotyledons 2. Embryo straight.
Special features. The flowering nodes separated by extended internodes. About 3–6 flowers subtended by each floral leaf. Calyx limb 5 lobed. Corolla tube not exceeding the calyx. The upper lip of the corolla incorporating 2 members, the lower 3; (posterior, adaxial) lip of the corolla entire. Lower (abaxial) lip of the corolla 3 lobed.
Geography, cytology, number of species. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, Northern Territory, and Queensland. Northern Botanical Province. A genus of 2 species, or 3 species; 1 species in Western Australia; 0 endemic to Western Australia.
Etymology. From the Greek for "unequal" and "limb"; the upper pair of anthers are single celled, while the lower pair are two celled.
FloraBase is produced by the staff of the Western Australian Herbarium, Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions. Publication or other use of content on this site is unauthorised unless that use conforms with the copyright statement.
Western Australian Herbarium (1998–). FloraBase—the Western Australian Flora. Department of Biodiversity, Conservation and Attractions. https://florabase.dpaw.wa.gov.au/