Habit and leaf form. Erect, branching herbs; bearing essential oils, or without essential oils (?); resinous, or not resinous (?). Annual, or biennial, or perennial. Leaves basal and cauline. To 0.2–1 m high; with a slender taproot. Helophytic, or mesophytic (?). Leaves small to large; alternate; ‘herbaceous’; petiolate. Petioles sheathing. Leaves more or less sheathing. Leaf sheaths with free margins. Leaves gland-dotted, or not gland-dotted (?); aromatic, or foetid, or without marked odour (?); simple, or compound; peltate, or not peltate (?); pulvinate, or epulvinate (?); when compound ternate, or pinnate, or bipinnate, or multiply compound (tripinnate). Leaflets ovate to obovate, or elliptic. Leaf blades when simple dissected (1–3-pinnatisect); pinnately veined. Leaves without stipules. Leaf blade margins serrate. Leaves without a persistent basal meristem. Leaf anatomy. Hairs absent (usually). Stem anatomy. Nodes multilacunar, or tri-lacunar (?). Secondary thickening developing from a conventional cambial ring, or anomalous (?); from a single cambial ring.
Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in umbels. Inflorescences compound. The terminal inflorescence unit cymose, or racemose. Inflorescences terminal and axillary; many-rayed, ray bracts entire. Flowers pedicellate. Pedicels spreading. Flowers bracteate. Bracts numerous, entire or pinnate. Flowers bracteolate. Bracteoles numerous, entire. Flowers small; regular to somewhat irregular (?); 5 merous (except for the gynoecium); cyclic; tetracyclic, or tricyclic (when calyx absent). Free hypanthium absent. Perianth with distinct calyx and corolla (but the calyx very reduced), or petaline; 5, or 10; 2 -whorled, or 1 -whorled; isomerous; white. Calyx vestigial, or absent; when detectable, 5; 1 -whorled; with the median member posterior. Corolla 5; 1 -whorled; polypetalous; valvate; unequal but not bilabiate, or regular (?); white. Petals ovate to obcordate; shortly clawed. Corolla members bilobed. Androecium 5. Androecial members free of the perianth; all equal to markedly unequal (?); free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 5; isomerous with the perianth; oppositisepalous; inflexed in bud. Filaments slender. Anthers dehiscing via longitudinal slits; introrse; tetrasporangiate. Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium syncarpous; synovarious; inferior. Ovary plurilocular; 2 locular. Gynoecium median. Epigynous disk present. Gynoecium stylate. Styles 2; free to partially joined (their bases thickened to form a depressed-conical stylopodium crowning the ovary); apical. Stigmas wet type; non-papillate; Group IV type. Placentation axile, or apical (?). Ovules 1 per locule, or 2 per locule (usually two, but one abortive ?); pendulous; epitropous; non-arillate; anatropous.
Fruit and seed features. Fruit non-fleshy; not hairy; a schizocarp. Mericarps 2 (united facially). Seeds 1 per mericarp. Seeds endospermic. Endosperm oily. Embryo well differentiated. Cotyledons 2. Embryo achlorophyllous; straight. Seedling. Germination phanerocotylar.
Physiology, biochemistry. Aluminium accumulation not found. Photosynthetic pathway: C3.
Geography, cytology, number of species. Adventive. Australian states and territories: Western Australia, South Australia, Queensland, New South Wales, and Victoria.
Additional characters Petals inflexed.