'', the elephant foot yam, a species cultivated in the tropical
Indo-Pacific for its edible
tubers with berry-like fruits These small to massive plants grow from a
subterranean tuber.
Amorphophallus tubers vary greatly from species to species, from the quite uniformly
globose tuber of
A. konjac to the elongated tubers of
A. longituberosus and
A. macrorhizus to the bizarre clustered rootstock of
A. coaetaneus. The weight of these tubers range from as little as in
Amorphophallus pusillus of Vietnam to as much as for
Amorphophallus titanum. 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 colours, 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, each with one
stamen, and then a blank sterile area. This last part, called 'the appendix', consists of sterile flowers, called
staminodes, and can be especially large. The flowers do not have
corollas. Mature female flowers are usually receptive for only one day. In many species, the inflorescence emits a scent of decaying flesh in order to attract insects, though a number of species give off a pleasant odour. Through a number of ingenious insect
traps, pollinating insects that entered a spathe when female flowers were receptive remain inside the spathe for about one day while male flowers mature and release pollen. Pollen falls on these insects, and they carry pollen as they exit the spathe and can pollinate female flowers in another spathe.
Amorphophallus species are used as food plants by the
larvae of some
Lepidoptera (
butterfly and
moth) species including
Palpifer sexnotatus and
Palpifer sordida. Pollinated flowers usually each develop into a globose
berry, a
fruit. The berries are red, orange-red, white, white and yellow, or blue, depending on the species.
Notable species The species
Amorphophallus titanum, 'corpse flower' or titan arum, has the world's largest unbranched
inflorescence, with a height of up to and a width of . After an over -tall flower opened at
Chicago Botanic Gardens on 29 September 2015, thousands lined up to see and smell it. The floriculturalist described it as smelling "like roadkill, a barnyard, a dirty diaper, very strong, a little bit of mothball smell too". Native to the Indonesian rainforest, it takes about 10 years to blossom. Dubbed "Alice", its bloom was broadcast via live webcam. It is one of two plants at the Chicago Botanic Gardens, which kept open until 2 am on September 30 to accommodate visitors. A runner-up is
Amorphophallus gigas, which is taller but has a somewhat smaller
inflorescence.
Amorphophallus konjac tubers are used to make , a Japanese thickening agent and edible jelly containing
glucomannan. Some species are called voodoo-lily, as are some species of
Typhonium (also in the Araceae). == Taxonomy and systematics ==