Spurge
Encyclopedia : S : SP : SPU : Spurge
Spurges (genus Euphorbia) are a very large and variable worldwide plant taxon, belonging to the spurge family, or Euphorbiaceae.
Origin of the name
The common name spurge derives from the Middle English / Old French: espurge, to purge, due to the use of the plants sap as purgative.The botanical name Euphorbia derives from the Greek Euphorbus, physician of king Juba II of Numidia (52-50 BC - 23 AD), in whose honour – or in allusion to his swollen belly – a certain plant he might have used (Euphorbia resinifera?) was named. In 1753 Carolus Linnaeus assigned the name to the entire genus (Spec. Pl. (ed. 1): 450). Type species is Euphorbia antiquorum L..
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.
Distribution
The genus is primarily found in the tropical and subtropical regions of Africa and the Americas, but also in temperate zones worldwide. Succulent species are mostly originated from Africa, the Americas and Madagascar.Taxonomy
The genus Euphorbia is one of the largest and most complex genera of flowering plants and several botanists have made unsuccessfully attempts to subdivide the genus into numerous smaller genera. Now according to recent DNA studies Euphorbia can be divided into 4 subgenera, each containing several not yet sufficiently studied sections and groups.
Subtribe Euphorbiinae
According to recent DNA studies the so called satellite genera around the huge genus Euphorbia in subtribe Euphorbiinae nest deep within Euphorbia. Consequently these satellites, namely the never generally accepted genus Chamaesyce as well as the smaller genera Elaeophorbia, Endadenium, Monadenium, Synadenium and Pedilanthus were transferred to Euphorbia by Steinmann & Porter (2002), Steinmann (2003) and Bruyns & al. (2006). Besides the yet remaining satellite genus Cubanthus which is closely related to Pedilanthus and hence will very likely be transferred to Euphorbia as well in the near future, the entire subtribe Euphorbiinae now consist of genus Euphorbia.Subgenera
- Esula
- Rhizanthium
- Chamaesyce
- Euphorbia S.Carter
Selected species
- Euphorbia albomarginata - Rattlesnake weed
- Euphorbia amygdaloides - Wood spurge
- Euphorbia cyparissias - Cypress spurge
- Euphorbia esula - Leafy spurge
- Euphorbia helioscopia - Sun Spurge
- Euphorbia heterophylla - Painted euphorbia, kaliko
- Euphorbia mellifera - Honey spurge
- Euphorbia myrsinites - Myrtle spurge
- Euphorbia poisonii
- Euphorbia pulcherrima - Poinsettia
- Euphorbia resinifera - Resin spurge
- Euphorbia tithymaloides - Redbird cactus, Devil's backbone
- Euphorbia virosa
Euphorbia species are used as food plants by the larvae of some Lepidoptera species including Giant Leopard Moth.
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 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
References
- [International Euphorbia Society]
- [Succulent Euphorbias]
- [A selection of important / new literature]
- [U4BA - Euphorbia for you]
- [Euphorbia and the other succulents]
- [The Euphorbia Family]
- [Spurge Web Cam]
- [ITIS]
- [IPNI]
- [Flora Zambesiaca: Euphorbia]
From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.