Amorphophallus (from Ancient Greek amorphos, "without form, misshapen" + phallos, "penis", referring to the shape of the prominent spadix) is a large genus of some 170 tropical and subtropical tuberous herbaceous plants from the Arum family (Araceae). A few species are edible as "famine foods" after careful preparation to remove irritating chemicals.
These are typical lowland plants, growing in the tropical and subtropical zones of the paleotropics, from West Africa to the Pacific Islands. None of them are found in the Americas although a remarkably similar but not closely related genus, Dracontium, has evolved there. Most species are endemic. They grow preferentially on disturbed grounds, such as secondary forests.
These small to massive plants grow from a subterranean tuber, Amorphophallus tubers vary greatly from species to species, from the quite uniformally globose tuber of A. konjac to the elongated tubers of A. longituberosus and A. macrorhizus to the bizarre clustered rootstock of A. coaetaneus. From the top of this tuber a single leaf, which can be several metres across in larger species, is produced atop a trunk like petiole followed, on maturity, by a single inflorescence. This leaf consists of a vertical leaf stalk and a horizontal blade, which may consist of a number of small leaflets. The leaf lasts one growing season. The peduncle (the primary flower stalk) can be long or short.
As is typical of the Arum family, these species develop an inflorescence consisting of an elongate or ovate spathe (a sheathing bract) which usually envelops the spadix (a flower spike with a fleshy axis). The spathe can have different colors, but mostly brownish-purple or whitish-green. On the inside, they contain ridges or warts, functioning as insect traps.
The plants are monoecious. The spadix has tiny flowers: female flowers, no more than a pistil, at the bottom, then male flowers, actually a group of stamens, and then a blank sterile area. This last part, called 'the appendix', consists of sterile flowers, called staminodes, and can be especially large. There is no corolla.
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