''Chaetachme'' is a monotypic genus of flowering plants native to eastern and western Africa, including

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

, containing the single species ''Chaetachme aristata''. Its

English English usually refers to: * English language * English people English may also refer to: Culture, language and peoples * ''English'', an adjective for something of, from, or related to England * ''English'', an Amish ter ...

common name is thorny elm, and it is known as ''muyuyu'' in

Kikuyu Kikuyu or Gikuyu (Gĩkũyũ) mostly refers to an ethnic group in Kenya or its associated language. It may also refer to: *Kikuyu people, a majority ethnic group in Kenya * Kikuyu language, the language of Kikuyu people *Kikuyu, Kenya, a town in Cen ...

. Traditionally placed in the Elm family, it is more recently placed in the family

Cannabaceae Cannabaceae is a small family of flowering plants, known as the hemp family. As now circumscribed, the family includes about 170 species grouped in about 11 genera, including '' Cannabis'' (hemp), '' Humulus'' (hops) and '' Celtis'' (hackberri ...

, thought to be possibly closely related to ''

Celtis ''Celtis'' is a genus of about 60–70 species of deciduous trees, commonly known as hackberries or nettle trees, in the hemp family Cannabaceae. It has a cosmopolitan distribution. Description ''Celtis'' species are generally medium-sized tree ...

''. ''Chaetachme aristata'' is a

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

or small

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

growing up to tall. It has drooping, angular branches covered with spines up to in length. The lance-shaped leaves are up to long by wide, pointed at the tip and smooth or serrated on the edges. The shrub is

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

and

sexually dimorphic Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

, with male and female flower types borne on separate individuals, although it may also be

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 ...

. This shrub is host to the mirid bug '' Volumnus chaetacme''. The spiny branches of the shrub are used as

fence A fence is a structure that encloses an area, typically outdoors, and is usually constructed from posts that are connected by boards, wire, rails or net (textile), netting. A fence differs from a wall in not having a solid foundation along its ...

s in African villages.

References

Cannabaceae Monotypic Rosales genera {{Rosales-stub