''Amorphophallus'' is a large genus of some 200 tropical and subtropical tuberous

herbaceous plant Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition o ...

s from the

arum ''Arum'' is a genus of plants in the Araceae family; they are native to Europe, northern Africa, and western and central Asia, with the highest species diversity in the Mediterranean region. Frequently called arum lilies, they are not closely ...

family (

Araceae The Araceae are a family of monocotyledonous flowering plants in which flowers are borne on a type of inflorescence called a spadix. The spadix is usually accompanied by, and sometimes partially enclosed in, a spathe (or leaf-like bract). Also ...

), native to

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

and various oceanic islands. The genus includes the Titan arum (''A. titanum'') of

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

, which has the largest

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

in the genus, and is known as the 'corpse flower' for the pungent odour it produces during its flowering period, which can take up to seven years of growth before it occurs. A few species are edible as "

famine food A famine food or poverty food is any inexpensive or ready available food used to nourish people in times of hunger and starvation, whether caused by extreme poverty, such as during economic depression or war, or by natural disasters such as dro ...

s" after careful preparation to remove irritating chemicals.

History

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 from

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

"without form, misshapen" and "

penis A penis (; : penises or penes) is a sex organ through which male and hermaphrodite animals expel semen during copulation (zoology), copulation, and through which male placental mammals and marsupials also Urination, urinate. The term ''pen ...

", referring to the shape of the prominent spadix. Between 1876 and 1911, Engler merged a number of other genera into ''Amorphophallus'', with a final

monograph A monograph is generally a long-form work on one (usually scholarly) subject, or one aspect of a subject, typically created by a single author or artist (or, sometimes, by two or more authors). Traditionally it is in written form and published a ...

published in 1911.

Distribution

These are typical lowland plants, growing in the tropical and subtropical zones of the

paleotropics The Paleotropical kingdom (Paleotropis) is a floristic kingdom composed of the tropical areas of Africa, Asia and Oceania (excluding Australia and New Zealand), as proposed by Ronald Good and Armen Takhtajan. Part of its flora is inherited fr ...

, 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 Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

. They grow preferentially on disturbed grounds, such as

secondary forest A secondary forest (or second-growth forest) is a forest or woodland area which has regenerated through largely natural processes after human-caused Disturbance (ecology), disturbances, such as Logging, timber harvest or agriculture clearing, or ...

Description

These small to massive plants grow from a subterranean

tuber Tubers are a type of enlarged structure that plants use as storage organs for nutrients, derived from stems or roots. Tubers help plants perennate (survive winter or dry months), provide energy and nutrients, and are a means of asexual reproduc ...

. ''Amorphophallus'' tubers vary greatly from species to species, from the quite uniformly

globose This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary ...

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 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 to as much as 305 pounds (139 kg) for ''

Amorphophallus titanum The titan arum (''Amorphophallus titanum'') is a flowering plant in the family Araceae. It has a large unbranched inflorescence; a tall single leaf, branched like a tree; and a heavy tuber which enables the plant to produce the inflorescence. ' ...

'', a 14,000 fold difference in weight. From the top of this tuber a single

leaf A leaf (: leaves) is a principal appendage of the plant stem, stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leav ...

, which can be several meters across in larger species, is produced atop a trunk-like petiole followed, on maturity, by a single

. 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 ''Arum'' is a genus of plants in the Araceae family; they are native to Europe, northern Africa, and western and central Asia, with the highest species diversity in the Mediterranean region. Frequently called arum lilies, they are not closely ...

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 Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system comparable with gynomonoecy, andromonoecy and trimonoecy, and contras ...

. The spadix has tiny flowers: female flowers, no more than a

pistil Gynoecium (; ; : gynoecia) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl (botany), whorl of a flower; it consists ...

, at the bottom, then male flowers, each with one

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

, 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

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e of some

Lepidoptera Lepidoptera ( ) or lepidopterans is an order (biology), order of winged insects which includes butterflies and moths. About 180,000 species of the Lepidoptera have been described, representing 10% of the total described species of living organ ...

(

butterfly Butterflies are winged insects from the lepidopteran superfamily Papilionoidea, characterized by large, often brightly coloured wings that often fold together when at rest, and a conspicuous, fluttering flight. The oldest butterfly fossi ...

and

moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ...

) species including '' Palpifer sexnotatus'' and '' Palpifer sordida''. Pollinated flowers usually each develop into a globose

berry A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit although many pips or seeds may be present. Common examples of berries in the cul ...

, a

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

. The berries are red, orange-red, white, white and yellow, or blue, depending on the species.

Notable species

The species ''

'', 'corpse flower' or titan arum, has the world's largest unbranched

, with a height of up to and a width of . After an over -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. A runner-up is '' Amorphophallus gigas'', which is taller, but has a somewhat smaller

. '' Amorphophallus konjac'' tubers are used to make , a Japanese thickening agent and edible jelly containing

glucomannan Glucomannan is a water-soluble polysaccharide that is considered a dietary fiber. It is a hemicellulose component in the Cell wall#Plant cell walls, cell walls of some plant species. Glucomannan is a food additive used as an emulsifier and thick ...

. Some species are called voodoo-lily, as are some species of '' Typhonium'' (also in the Araceae).

Taxonomy and systematics

The genus was divided into 4 subgenera based on

phylogenetic analysis In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data ...

in 2017, with a number of SE Asian genera currently unplaced:

Subgenus Amorphophallus

Subgenus Scutrandrium

Subgenus Metandrium

Subgenus Afrophallus

Subgenus unplaced

* '' Amorphophallus gliruroides'' Engl. – Myanmar * '' Amorphophallus incurvatus'' Alderw. – Sumatra * '' Amorphophallus lyratus'' (Roxb.) Kunth – SE India * '' Amorphophallus mekongensis'' Engl. & Gehrm. –

Indochina Mainland Southeast Asia (historically known as Indochina and the Indochinese Peninsula) is the continental portion of Southeast Asia. It lies east of the Indian subcontinent and south of Mainland China and is bordered by the Indian Ocean to th ...

* '' Amorphophallus paucisectus'' Alderw. – Sumatra * '' Amorphophallus perakensis'' Engl. – Peninsula Malaysia

References

Bibliography

* 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. *

External links

List of ''Amorphophallus'' species with photos
from the International Aroid Society *
''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. {{Authority control Araceae genera Taxa named by Joseph Decaisne