Amorphophallus

The oldest systematic record of the plants was in 1692, when Van Rheede tot Drakenstein published descriptions of two plants. The name "Amorphophallus" was first mentioned in 1834 by the Dutch botanist Blume{{cite journal | last1=Hetterscheid |first1=W. |last2=Ittenbach |first2=S. |year=1990 |title=Everything you always wanted to know about Amorphophallus but were afraid to stick your nose into! |journal=Aroideana |volume=19 |page=17-20}} from Ancient Greek {{lang|el|αμορφος}} amorphos "without form, misshapen" and {{lang|el|φαλλος}} phallos "penis", referring to the shape of the prominent spadix.{{citation needed | date=March 2025}} Between 1876 and 1911, Engler{{who | date=March 2025}} merged a number of other genera into Amorphophallus, with a final monograph published in 1911.

These are typical lowland plants, growing in the tropical and subtropical zones of the paleotropics, from West Africa through 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.{{Cite web|last=Design|first=UBC Web|title=Bulbs, White, House, Nursery|url=https://www.whitehousenursery.com.au/|access-date=2021-12-08|website=Amorphophallus Conjak {{!}} White House Nursery|language=en}}

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File:Amorphophallus paeoniifolius (Philippines) 5.jpg, the elephant foot yam, a species cultivated in the tropical Indo-Pacific for their edible tubers]]

Image:Amorphophallus_sp._fruit.jpg

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. It can grow up to 6 feet in height and the weight of these tubers range from as little as ten grams (3/10ths of an ounce) in Amorphophallus pusillus of Vietnam{{cite book | last= Bown | first= Deni | date= 2000 | title= Aroids - Plants of the Arum Family | location= Portland | publisher= Timber Press | page= 236 }} to as much as 305 pounds (139 kg) for Amorphophallus titanum, a 14,000 fold difference in weight. From the top of this tuber a single leaf, which can be several meters 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, 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 odor. 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.

The species Amorphophallus titanum, 'corpse flower' or titan arum, has the world's largest unbranched inflorescence, with a height of up to {{convert|2.5|m|ft}} and a width of {{convert|1.5|m|ft}}.{{citation needed|date=September 2015}} After an over {{convert|1.2|m|ft}}-tall flower opened at Chicago Botanic Gardens on September 29, 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.{{cite web|title=Thousands line up to see huge stinky flower|url=https://www.reuters.com/video/2015/09/30/thousands-line-up-to-see-huge-stinky-flo?videoId=365778165&videoChannel=118169|website=Reuters Editors' Picks|publisher=Reuters|access-date=30 September 2015|date=30 September 2015|format=video|quote=Chicago's floral celebrity is over four feet tall, incredibly rare, and smells like death}}

A runner-up is Amorphophallus gigas, which is taller, but has a somewhat smaller inflorescence.{{citation needed|date=September 2015}}

Amorphophallus konjac tubers are used to make {{nihongo|konnyaku|コンニャク}}, a Japanese thickening agent and edible jelly containing glucomannan.{{Cite journal |last1=Fang |first1=Yimeng |last2=Ma |first2=Jiahui |last3=Lei |first3=Pengyu |last4=Wang |first4=Lei |last5=Qu |first5=Junying |last6=Zhao |first6=Jing |last7=Liu |first7=Fan |last8=Yan |first8=Xiaoqing |last9=Wu |first9=Wei |last10=Jin |first10=Libo |last11=Ji |first11=Hao |last12=Sun |first12=Da |date=2023-01-12 |title=Konjac Glucomannan: An Emerging Specialty Medical Food to Aid in the Treatment of Type 2 Diabetes Mellitus |journal=Foods |language=en |volume=12 |issue=2 |pages=363 |doi=10.3390/foods12020363 |doi-access=free |issn=2304-8158 |pmc=9858196 |pmid=36673456}}

Some species are called voodoo-lily, as are some species of Typhonium (also in the Araceae).{{Cite news|url=https://wimastergardener.org/article/voodoo-lily-amorphophallus-konjac/|title=Voodoo Lily, Amorphophallus konjac|work=Master Gardener Program|access-date=2018-01-18|language=en-US}}{{Cite web|url=http://pacificbulbsociety.org/pbswiki/index.php/Sauromatum|title=Pacific Bulb Society {{!}} Sauromatum|website=pacificbulbsociety.org|access-date=2018-01-18}}

{{Cladogram|style="float:right;"|title=Amorphophallus Subgenera

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|1 =Subgenus Scutrandrium

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| 1 = Subgenus Amorphophallus

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| 2 = Subgenus Metandrium

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| 1 = Subgenus Afrophallus

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The genus was divided into 4 subgenera based on phylogenetic analysis in 2017,{{cite journal | last1=Claudel | first1=Cyrille | last2=Buerki | first2=Sven | last3=Chatrou | first3=Lars W. | last4=Antonelli | first4=Alexandre | last5=Alvarez | first5=Nadir | last6=Hetterscheid | first6=Wilbert | title=Large-scale phylogenetic analysis of Amorphophallus (Araceae) derived from nuclear and plastid sequences reveals new subgeneric delineation | journal=Botanical Journal of the Linnean Society | publisher=Oxford University Press (OUP) | volume=184 | issue=1 | date=2017-05-01 | issn=0024-4074 | doi=10.1093/botlinnean/box013 | pages=32–45| doi-access=free }} with a number of SE Asian genera currently unplaced:

• Amorphophallus gliruroides Engl. - Myanmar
• Amorphophallus incurvatus Alderw. - Sumatra
• Amorphophallus lyratus (Roxb.) Kunth - SE India
• Amorphophallus mekongensis Engl. & Gehrm. - Indochina
• Amorphophallus paucisectus Alderw. - Sumatra
• Amorphophallus perakensis Engl. - Peninsula Malaysia

{{Reflist}}

• Hetterscheid, W.L.A. 1994. Preliminary taxonomy and morphology of Amorphophallus Blume ex Decaisne (Araceae). In: M.M. Serebreyanyi (ed.), Proc. Moscow Aroid Conference 1992: 35-48. Moscow.
• Hetterscheid, W.L.A. & G.J.C.M. v. Vliet, 1996. Amorphophallus, giant from the forest. CITES/C&M, 2(4): 86-96.

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{{Wikispecies}}

• [http://www.aroid.org/genera/generapage.php?genus=amorphophallus List of Amorphophallus species with photos] from the International Aroid Society
• [https://web.archive.org/web/20110426184634/http://www.cate-araceae.org/taxonomy/Amorphophallus CATE genus page]
• [http://www.westafricanplants.senckenberg.de/root/index.php?page_id=13&preview=true&searchTextMenue=amorphophallus&search=W+Afr+Pl Amorphophallus] in Brunken, U., Schmidt, M., Dressler, S., Janssen, T., Thiombiano, A. & Zizka, G. 2008. West African plants - A Photo Guide. Forschungsinstitut Senckenberg, Frankfurt/Main.

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Category:Araceae genera

Category:Taxa named by Joseph Decaisne