''Spathiostemon'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of trees in the

Euphorbiaceae Euphorbiaceae, the spurge family, is a large family of flowering plants. In English, they are also commonly called euphorbias, which is also the name of a genus in the family. Most spurges, such as ''Euphorbia paralias'', are herbs, but some, e ...

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

. It is native to the

Bismarck Archipelago The Bismarck Archipelago (, ) is a group of islands off the northeastern coast of New Guinea in the western Pacific Ocean and is part of the Islands Region of Papua New Guinea. Its area is about 50,000 square km. History The first inhabitants o ...

New Guinea New Guinea (; Hiri Motu Hiri Motu, also known as Police Motu, Pidgin Motu, or just Hiri, is a language of Papua New Guinea, which is spoken in surrounding areas of Port Moresby (Capital of Papua New Guinea). It is a simplified version of ...

Wallacea Wallacea is a biogeographical designation for a group of mainly Indonesian islands separated by deep-water straits from the Asian and Australian continental shelves. Wallacea includes Sulawesi, the largest island in the group, as well as Lo ...

and

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

. The trees grow between 10 and 20m tall, often in secondary forest. The wood is sometimes used.

Description

The two species occur as trees or shrubs up to 20m tall. They 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 alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is conne ...

, that is individual trees have both female and male flowers though the sexes flower at different times. Leaves are spirally arranged and simple in form, papery. Flowers do not have petals. Woody thin-walled capsules are slightly lobed, glabrous (hairless) and either smooth or spiny. There are usually 2-3 seeds per fruit, obovoid (rounded at both ends), and slightly triangular in cross/transverse section. The genus is distinguished from other Malesian Euphorbiaceae by the following traits: if present the latex is not obvious; hairs are present; pistillate (female) flowers have apically split stigmas; the male (staminate) flowers have stamens that split into two equal branches, arising from 4‒7 androphores/stalks, with ultimately more than 100 stamens.

History

Carl Ludwig Blume Charles Ludwig de Blume or Karl Ludwig von Blume (9 June 1796, Braunschweig – 3 February 1862, Leiden) was a German-Dutch botanist. He was born at Braunschweig in Germany, but studied at Leiden University and spent his professional life wor ...

, botanist, was born in

Braunschweig Braunschweig () or Brunswick ( , from Low German ''Brunswiek'' , Braunschweig dialect: ''Bronswiek'') is a city in Lower Saxony, Germany, north of the Harz Mountains at the farthest navigable point of the river Oker, which connects it to the Nor ...

, but mainly worked in the Netherlands and the

Netherlands East Indies The Dutch East Indies, also known as the Netherlands East Indies ( nl, Nederlands(ch)-Indië; ), was a Dutch colony consisting of what is now Indonesia. It was formed from the nationalised trading posts of the Dutch East India Company, which ...

. He first described ''Spathiostemon'' as a genus in 1826 in the journal ''Bijdragen tot de Flora van Nederlandsch Indie''.

Species

* ''

Spathiostemon javensis ''Spathiostemon javensis'' is a plant that can grow as a shrub or a tree in the tribe Acalypheae of the family Euphorbiaceae. It is native to the region from the Bismarck Archipelago to New Guinea, Wallacea and into Southeast Asia. It is often co ...

'' Blume - Bismarck Archipelago, New Guinea, Maluku, Lesser Sunda Islands, Sulawesi, Philippines, Jawa, Borneo, and Peninsular Malaysia * '' Spathiostemon moniliformis''

Airy Shaw Herbert Kenneth Airy Shaw (7 April 1902 – 1985) was a notable English botanist and classicist. Airy Shaw was born at The Mount, Grange Road, Woodbridge, Suffolk to a father serving as Second Master at the Woodbridge Grammar School and a mother ...

- Southern Thailand

Formerly included

* ''Spathiostemon forbesii'' (

S.Moore Spencer Le Marchant Moore (1 November 1850 – 14 March 1931) was an English botanist. Biography Moore was born in Hampstead. He worked at the Royal Botanic Gardens, Kew, from about 1870 to 1879, wrote a number of botanical papers, and then work ...

) Airy Shaw - '' Clonostylis forbesii'' S.Moore * ''Spathiostemon salicinus'' (

Hassk. Justus Carl Hasskarl (6 December 1811 – 5 January 1894) was a German explorer and botanist specializing in Pteridophytes, Bryophytes and Spermatophytes. He was co-founder of the Society of Natural Curiosities of India, in Bavaria and spent his ...

) Hassk. - ''

Homonoia riparia ''Homonoia riparia'', the willow-leaved water croton, a mangrove species, belongs to the family Euphorbiaceae. The plant is widely distributed through South Asian and South East Asian countries such as Cambodia, China, Indonesia, Laos, Papua New ...

'' Lour.

References

Euphorbiaceae genera {{Euphorbiaceae-stub