Spurge

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{{Taxobox | color = lightgreen | name = Spurge | image = Euphorbiacotinifolia1web.jpg | image_width = 250px | image_caption = Euphorbia cotinifolia ssp. cotinoides | regnum = Plantae | divisio = Magnoliophyta | classis = Magnoliopsida | ordo = Malpighiales | familia = Euphorbiaceae | subfamilia = Euphorbioideae | tribus = Euphorbieae | subtribus = Euphorbiinae | genus = Euphorbia | genus_authority = L. | diversity = More than 2000 species worldwide | diversity_link = List of Euphorbia species | subdivision_ranks = Species | subdivision =

See full list.

}}

Spurges (genus Euphorbia) are a very large and variable worldwide plant taxon, belonging to the namesake family (spurge family, or Euphorbiaceae). The name "Euphorbia" comes from a Greek surgeon named Euphorbus, who supposedly used the milky latex of these plants in his potions.

Contents

Description

The genus ranges from small trees, shrubs, vines to herbaceous plants. A significant percentage of these are succulent plant, some of which remarkably resemble cacti despite being unrelated, an example of convergent evolution. To the exception of a few species (i.e. Euphorbia hedytoides or Euphorbia curtisii), this genus is composed of monoecious species.

Spurges have a highly specialized inflorescence: the cyathium, which are reduced unisexual flowers grouped into characteristic pseudanthia. It consists of a central pistillate flower surrounded by five groups of staminate flowers. All flowers are enclosed within an involucre with four marginal glands. The central flower develops before the surrounding male ones, thus each cyathium functions like a protogynous hermaphrodite flower. The glands of the cyathium usually produce nectar, and pollination is mainly zoophilous. Indeed, the cyathium looks so much like a hermaphrodite flower that Carolus Linnaeus and other authors interpreted it as a true flower. Jean-Baptiste Lamarck however interpreted the cyathium as an inflorescence and this is now recognized.

Spurges contain an acrid, poisonous milky latex, and some of them are armed with thorns. Most of the spurges yield powerful emetic and cathartic products.

Euphorbia species are used as food plants by the larvae of some Lepidoptera species including Giant Leopard Moth.

Distribution

The genus is primarily found in the tropical regions of Africa and the Americas, but also in temperate zones. Succulent species are mostly originated from Africa and Madagascar.

Taxonomy

The genus Euphorbia is one of the largest and most complex genera of flowering plants; several botanists have made attempts to subdivide the genus into numerous smaller genera, but to date, these segregate genera have not generally been recognised:

Selected species

See List of Euphorbia species.

Literature

  • Schwartz, Herman (Ed.): The Euphorbia Journal Vol. 1 Strawberry Press, Mill Valley, California, USA 1983. ISBN 0-912647-0-0
  • Schwartz, Herman (Ed.): The Euphorbia Journal Vol. 2 Strawberry Press, Mill Valley, California, USA 1984. ISBN 0-912647-01-9
  • Schwartz, Herman (Ed.): The Euphorbia Journal Vol. 3 Strawberry Press, Mill Valley, California, USA 1985. ISBN 0-912647-02-7
  • Schwartz, Herman (Ed.): The Euphorbia Journal Vol. 4 Strawberry Press, Mill Valley, California, USA 1987. ISBN 0-912647-04-3
  • Schwartz, Herman (Ed.): The Euphorbia Journal Vol. 5 Strawberry Press, Mill Valley, California, USA 1988. ISBN 0-912647-05-1
  • Schwartz, Herman (Ed.): The Euphorbia Journal Vol. 6 Strawberry Press, Mill Valley, California, USA 1989. ISBN 0-912647-06-x
  • Schwartz, Herman (Ed.): The Euphorbia Journal Vol. 7 Strawberry Press, Mill Valley, California, USA 1991. ISBN 0-912647-08-6
  • Schwartz, Herman (Ed.): The Euphorbia Journal Vol. 8 Strawberry Press, Mill Valley, California, USA 1992. ISBN 0-912647-10-8
  • Schwartz, Herman (Ed.): The Euphorbia Journal Vol. 9 Strawberry Press, Mill Valley, California, USA 1994. ISBN 0-912647-11-6
  • Schwartz, Herman (Ed.): The Euphorbia Journal Vol. 10 Strawberry Press, Mill Valley, California, USA 1996. ISBN 0-912647-15-0
  • Singh, Meena: Succulent Euphorbiaceae of India Selbstverlag, New Delhi, India 1994 (Mrs. Meena Singh, A-162 Sector 40, NOIDA - 201303, India)
  • Buddensiek, Volker Succulent Euphorbia plus Volker Buddensiek Verlag 2005, CD-ROM. ISBN 3-934396-03-8
  • Noltee, Frans: Succulents in the wild and in cultivation, Part 2 Euphorbia to Juttadinteria 2001, CD-ROM. ISBN 90-76774-05-6
  • Turner, Robert: Euphorbias - A Gardeners' Guide Timber Press, 1998. ISBN 0-88192-419-9
  • Carter, Susan: New Succulent Spiny Euphorbias from East Africa, 1982. ISBN 1878762729
  • Carter, Susan & Smith, A.L.: Flora of Tropical East Africa, Euphorbiaceae 1988. ISBN 9061913381
  • Carter, Susan & Eggli,Urs: The CITES Checklist of Succulent Euphorbia Taxa (Euphorbiaceae) 1997. ISBN 3896246097
  • Pritchard, Albert: Introduction to the Euphorbiaceae 2003. ISBN 8890051132

Reference

Template:Commons ITIS - Euphorbia
as of 2002-07-13de:Wolfsmilch eo:Eŭforbio fr:Euphorbe nl:Wolfsmelk pl:Wilczomlecz pt:Euphorbia