Description from Flora of China
Herbs, seasonally dormant. Underground part a long or short tuberous rhizome. Leaves entire, sagittate-hastate, 3-lobed or -partite. Inflorescence simultaneous with or preceding leaves; peduncle short or long. Spathe divided into a strongly convolute basal part with a ± strong apical constriction and a spreading lanceolate to ovate-triangular limb. Spadix as long as or longer than spathe, with 4 zones: a proximal female zone, an intermediate sterile zone with staminodes all over (in Typhonium flagelliforme only) or only at base, a male zone, and a sessile or stipitate appendix. Female flowers 1-loculed with 1 or 2(or 3) orthotropous basal ovules. Staminodes variable, spatulate to filamentous or variously reduced. Male flowers with 1-3 stamens opening by slits or pores; connective sometimes prolonged. Fruiting zone with spathe remaining (sometimes splitting open at maturity); berries ovoid, 1(or 2)-seeded. Seeds with endosperm.
The number of species given here for China is expected to be a considerable underestimation in view of the high species numbers in N Thailand and N Vietnam.
Recent molecular investigation of the tribe Areae (Cusimano et al, Taxon 59: 439-447. 2010) suggested that Typhonium sensu Hetterscheid and Boyce (Aroideana 23: 48-55. 2000) is polyphyletic and transferred several species to Sauromatum. The latter genus in its new monophyletic circumscription was shown not to be the direct sister genus to Typhonium sensu stricto.
About 50 species: from India to Polynesia; distributions in Africa and the West Indies are the result of human introductions; nine species (four endemic) in China.
(Authors: Li Heng (李恒 Li Hen); Wilbert L. A. Hetterscheid)