Erect, seasonally dormant herbs with subglobose tubers (rarely rhizomatous in some Asian species). Leaves radical, 1–3, subtended by several cataphylls; petioles not pulvinate apically; sheaths long, often imbricate to form a pseudostem; blade compound, pedately to radiately divided to base into elliptic to obovate acuminate lobes; primary lateral veins of lobes usually forming inframarginal veins, finer venation reticulate. Inflorescence erect, terminal, solitary, appearing with leaves. Spathe convolute basally into a ± cylindric tube, upper part (limb) expanded, forward-curving or ± erect, acuminate, variously coloured or striped. Spadix unisexual (paradioecious) or monoecious with basal pistillate part contiguous with central staminate part, always with terminal, sterile, smooth appendix of variable shape from clavate to filamentous, usually subcylindric in African species. Flowers unisexual, without perigon. Staminate flowers ± distant, each with 2–5 stamens; filaments connate; anthers free to connate, dehiscing by pores or straight to lunate slits; connective slender. Pistillate flowers congested; ovary unilocular; ovules 1–9; placentation basal; stigma sessile or on short conic style, capitate. Berries fleshy, glossy orange to scarlet, few-seeded, borne in cylindric to conic infructescence. Seeds subglobose; endosperm copious; embryo axile.
Herbs, terrestrial or wetland. Corms [rhizomes] nearly globose. Leaves usually appearing with flowers, 1--2(--3), erect; petiole longer than blade; blade medium to dark green, sometimes glaucous adaxially, palmately or pedately [radiately] divided, not peltate, leaflet elliptic to broadly ovate or oblanceolate, base rounded to obtuse or attenuate, apex obtuse or acute to acuminate; primary lateral veins of each leaflet pinnate. Inflorescences: peduncle erect, nearly equal to leaves [to very short], apex not swollen; spathe variously colored or striped, distal part open at maturity, exposing tip to 1/2 or more of spadix appendage; spadix ± cylindric, surmounted by sterile appendage of variable shape. Flowers unisexual, staminate and pistillate on same or different spadix; pistillate flowers congested; staminate flowers usually scattered, distal to pistillate flowers when both are present; perianth absent. Fruits not embedded in spadix, glossy orange to bright red. Seeds 1--6, mucilage sometimes present (not present in Arisaema triphyllum). x = 13, 14.
Monoecious or dioecious; fls covering the basal part of a fleshy spadix that is subtended by a green or purple-brown spathe; perianth none; staminate fls above the pistillate, composed of 2–5 subsessile anthers opening apically; pistillate fls consisting of a unilocular ovary with 1–several basal orthotropous ovules and a broad stigma; fr a cluster of globose red berries, each with 1–3 seeds; cormose perennials with long-petioled compound lvs. 150, irregularly cosmop.