A genus of about 150-170 species, of Asia, e. North America, e. Africa, and Arabia. Infrageneric taxonomy follows Ohi-Toma et al. (2016). The taxa of the Arisaema triphyllum complex have been variously treated as species, subspecies, varieties, and forms. They are here treated as species with relatively subtle morphological distinctions; they are broadly sympatric, and sometimes occur together in mixed populations with little sign of introgression or hybridization and seem to behave as biological species. Arisaema quinatum has often been treated as a full species and seems to warrant that status. Arisaema stewardsonii seems amply distinct in morphology, northern distribution, and boggy habitat. Arisaema triphyllum is tetraploid and does not produce fertile seed when crossed with the other (diploid) taxa, including A. pusillum, with which it is broadly sympatric (Treiber 1980). The size (though diploid) and strongly attenuated spathe apex seem good reason to accord A. acuminatum species status as well.
ID notes:Arisaema can be confused in vegetative condition with Pinellia; see Araceae key to genera.
Ref: Gusman & Gusman (2002); Huttleston (1949); Huttleston (1981); Mayo, Bogner, & Boyce In Kubitzki (1998b); Renner, Zhang, & Murata (2004); Spaulding et al. (2019); Thompson (2000b) In Flora of North America Editorial Committee (2000); Treiber (1980); Ward (2012b); Wyatt & Stoneburner (2022). Show full citations.