Overview

Comprehensive Description

Description

Monoecious annual, biennial or perennial herbs, shrubs or trees, sometimes succulent. Milky latex present. Stipules usually present. Leaves mostly alternate, sometimes opposite or whorled. Inflorescence composed of cyathia in simple, dichotomous or umbellate terminal cymes; bracts paired, often leaf-like, sometimes brightly coloured. Cyathia with (1-)4-5(-8) glands around the rim alternating with 5 fringed lobes. Male flowers in 5 groups separated by fringed membranes, bracteolate. Female flower subsessile or with the pedicel elongating or reflexed in fruit. Ovary 3-locular. Styles 3, partly united. Fruit a dehiscent capsule, usually 3-lobed.
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© Mark Hyde, Bart Wursten and Petra Ballings

Source: Flora of Zimbabwe

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Ecology

Associations

Foodplant / gall
Heterodera cacti causes gall of cysted root of Euphorbia (succulent spp)

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Foodplant / open feeder
larva of Aphthona atrocaerulea grazes on leaf of Euphorbia

Foodplant / open feeder
larva of Aphthona euphorbiae grazes on leaf of Euphorbia

Foodplant / open feeder
larva of Aphthona melancholica grazes on leaf of Euphorbia

Foodplant / gall
larva of Bayeria capitigena causes gall of shoot tip of Euphorbia
Other: sole host/prey

Foodplant / open feeder
adult of Cryptocephalus moraei grazes on live flower of Euphorbia
Remarks: season: 5-9

Foodplant / sap sucker
nymph of Dicranocephalus agilis sucks sap of Euphorbia

Foodplant / parasite
sporangium of Peronospora euphorbiae parasitises live Euphorbia

Foodplant / spot causer
Xanthomonas axonopodis pv. poinsettiicola causes spots on live leaf of Euphorbia

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Evolution and Systematics

Functional Adaptations

Functional adaptation

Waxy coating protects from heat and drought: euphorbia
 

The stems of euphorbias protect from heat and drought via their hard waxy surface.

     
  "On the ground around them grow numerous fat, spiny leafless plants that any non-botanist could be forgiven for calling -- without hesitation and even perhaps a certain amount of pride in his expertise -- cacti. Only if they are in flower might you suspect that they are not. Then a botanist would notice that the numbers of petals and anthers are quite different from those of cacti. These are euphorbias, members of one of the largest of all families of flowering plants with over seven thousand species. In Europe, its common representatives are dog's mercury and spurge. In South America, euphorbias grow into trees and shrubs, among them the rubber tree and the manioc plant. In African forests, its members include the castor oil bush. And in African deserts they become cacti look-alikes…The cactus family is, in fact, exclusively American, with hundreds of different species growing in deserts from Canada to Chile. The reason that members of these two families resemble one another so closely is that similar conditions of heat and drought have stimulated the same physical response. Both abandon their leaves at an early stage, since these inevitably lose a great deal of water, and both carry out their photosynthesis under the hard waxy surface of their stems which are green with chlorophyll. Both store water in a bloated pillar-like trunk. And both defend that water from robbers by armouring their trunks with sharp spines." (Attenborough 1995:272-275)
  Learn more about this functional adaptation.
  • Attenborough, D. 1995. The Private Life of Plants: A Natural History of Plant Behavior. London: BBC Books. 320 p.
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Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage

Barcode of Life Data Systems (BOLD) Stats
Specimen Records: 1272
Specimens with Sequences: 1297
Specimens with Barcodes: 715
Species: 493
Species With Barcodes: 432
Public Records: 393
Public Species: 79
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Source: Barcode of Life Data Systems (BOLD)

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Barcode data

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Wikipedia

Euphorbia

Not to be confused with euphoria.

Euphorbia is a diverse genus of flowering plants belonging to the family Euphorbiaceae, and is the type genus of the family. Consisting of 2008 species,[1] Euphorbia is the fourth largest genus of flowering plants; it also has one of the largest ranges of chromosome counts, along with Rumex and Senecio.[2] Members of the family and genus are commonly called spurges. Euphorbia antiquorum is the type species for the genus Euphorbia;[3] it was described by Carl Linnaeus in 1753 in Species Plantarum. The family is primarily found in the tropical and subtropical regions of Africa and the Americas, but also in temperate zones worldwide. Succulent species originate mostly from Africa, the Americas and Madagascar. There exists a wide range of insular species: on the Hawaiian Islands, where spurges are collectively known as "akoko",[4] and on the Canary Islands as "tabaibas".[5][6]

The common name "spurge" derives from the Middle English/Old French espurge ("to purge"), due to the use of the plant's sap as a purgative.

The botanical name Euphorbia derives from Euphorbus, the Greek physician of king Juba II of Numidia (52–50 BC – 23 AD), who married the daughter of Anthony and Cleopatra.[7] He wrote that one of the cactus-like Euphorbias was a powerful laxative.[7] In 12 B.C., Juba named this plant after his physician Euphorbus in response to Augustus Caesar dedicating a statue to Antonius Musa, his own personal physician.[7] Botanist and taxonomist Carl Linnaeus assigned the name Euphorbia to the entire genus in the physician's honor.[8]

Description[edit]

The plants are annual or perennial herbs, woody shrubs or trees with a caustic, poisonous milky sap (latex). The roots are fine or thick and fleshy or tuberous. Many species are more or less succulent, thorny or unarmed. The main stem and mostly also the side arms of the succulent species are thick and fleshy, 15–91 cm (6–36 inches) tall. The deciduous leaves are opposite, alternate or in whorls. In succulent species the leaves are mostly small and short-lived. The stipules are mostly small, partly transformed into spines or glands, or missing.

Like all members of the family Euphorbiaceae, all spurges have unisexual flowers. In Euphorbia these are greatly reduced and grouped into pseudanthia called cyathia. The majority of species are monoecious (bearing male and female flowers on the same plant), although some are dioecious with male and female flowers occurring on different plants. It is not unusual for the central cyathia of a cyme to be purely male, and for lateral cyathia to carry both sexes. Sometimes young plants or those growing under unfavorable conditions are male only, and only produce female flowers in the cyathia with maturity or as growing conditions improve. The bracts are often leaf-like, sometimes brightly coloured and attractive, sometimes reduced to tiny scales. The fruits are three (rarely two) compartment capsules, sometimes fleshy but almost always ripening to a woody container that then splits open (explosively, see explosive dehiscence). The seeds are 4-angled, oval or spherical, and in some species have a caruncle.

Xerophytes and succulents[edit]

In the genus Euphorbia, succulence in the species has often evolved divergently and to differing degrees. Sometimes it is difficult to decide, and it is a question of interpretation, whether or not a species is really succulent or "only" xerophytic. In some cases, especially with geophytes, plants closely related to the succulents are normal herbs. About 850 species are succulent in the strictest sense. If one includes slightly succulent and xerophytic species, this figure rises to about 1000, representing about 45% of all Euphorbia species.

Irritance[edit]

The milky sap of spurges (called "latex") evolved as a deterrent to herbivores. It is white and colorless when dry, except in E. abdelkuri, where it is yellow. The pressurized sap seeps from the slightest wound and congeals after a few minutes in air. The skin irritating and caustic effects are largely caused by varying amounts of diterpenes. Triterpenes such as betulin and corresponding esters are other major components of the latex.[9] In contact with mucous membranes (eyes, nose, mouth), the latex can produce extremely painful inflammation. Therefore, spurges should be handled with caution and kept away from children and pets. Latex on skin should be washed off immediately and thoroughly. Congealed latex is insoluble in water, but can be removed with an emulsifier like milk or soap. A physician should be consulted if inflammation occurs, as severe eye damage including permanent blindness may result from exposure to the sap.[10] When large succulent spurges in a greenhouse are cut, vapours can cause irritation to the eyes and throat several metres away. Precautions, including sufficient ventilation, are required.

Uses[edit]

Detail of Poinsettia flowers and immature fruits
An old Euphorbia hybrid

Several spurges are grown as garden plants, among them Poinsettia (E. pulcherrima) and the succulent E. trigona. E. pekinensis (Chinese: 大戟; pinyin: dàjǐ) is used in traditional Chinese medicine, where it is regarded as one of the 50 fundamental herbs. Several Euphorbia species are used as food plants by the larvae of some Lepidoptera (butterflies and moths), like the Spurge Hawk-moths (Hyles euphorbiae and Hyles tithymali), as well as the Giant Leopard Moth.

The diterpenoid ingenol is the core structure of a topical drug recently commercialized to treat actinic keratosis, a precancerous skin condition. It is produced by the Euphorbia plants.

Euphorbia is often used as a hedging plant in many parts of Africa.[11]

Systematics and taxonomy[edit]

According to recent studies of DNA sequence data,[12][13][14] most of the smaller "satellite genera" around the huge genus Euphorbia nest deep within the latter. Consequently these taxa, namely the never generally accepted genus Chamaesyce as well as the smaller genera Cubanthus,[15] Elaeophorbia, Endadenium, Monadenium, Synadenium and Pedilanthus were transferred to Euphorbia. The entire subtribe Euphorbiinae now consists solely of the genus Euphorbia.

Selected species[edit]

See List of Euphorbia species for complete list.

Subgenera[edit]

Simplified diagram of relations in subtribe Euphorbiinae

The genus Euphorbia is one of the largest and most complex genera of flowering plants and several botanists have made unsuccessful attempts to subdivide the genus into numerous smaller genera. According to the recent phylogenetic studies,[12][13][14] Euphorbia can be divided into 4 subgenera, each containing several not yet sufficiently studied sections and groups. Of these, Esula is the most basal. Chamaesyce and Euphorbia are probably sister taxa but very closely related to Rhizanthium. Extensive xeromorph adaptations in all probability evolved several times; it is not known if the common ancestor of the cactus-like Rhizanthium and Euphorbia lineages was xeromorphic—in which case a more normal morphology would have re-evolved namely in Chamaesyce—or whether extensive xeromorphism is entirely polyphyletic even to the level of the subgenera.

  • Rhizanthium

References[edit]

  1. ^ "WCSP". World Checklist of Selected Plant Families. Retrieved 2011-04-16. 
  2. ^ Stebbins, G. L.; Hoogland, R. D. (1976). "Species diversity, ecology and evolution in a primitive Angiosperm genus:Hibbertia (Dilleniaceae)". Plant Systematics and Evolution 125 (3): 139. doi:10.1007/BF00986147.  edit
  3. ^ S. Carter (2002). "Euphorbia". In Urs Eggli. Dicotyledons. Illustrated Handbook of Succulent Plants 5. Springer. p. 102. ISBN 978-3-540-41966-2. 
  4. ^ Module 14: Hawaiian in A Mini-Course in Medical Botany
  5. ^ tabaibas
  6. ^ http://buscon.rae.es/draeI/SrvltConsulta?TIPO_BUS=3&LEMA=tabaiba
  7. ^ a b c Nancy Dale (1986). Flowering Plants of the Santa Monica Mountains. California Native Plant Society. p. 107. ISBN 978-0-88496-239-7. 
  8. ^ Carl Linnaeus (1753). "Euphorbia". Species Plantarum (1st ed.). p. 450. 
  9. ^ Research into Euphorbia latex and irritant ingredients. Collected by Dr. Richard J. Hodgkiss. Retrieved November 2, 2013.
  10. ^ Tom Eke, Sahar Al-Husainy & Mathew K. Raynor (2000). "The spectrum of ocular inflammation caused by Euphorbia plant sap" (PDF). Arch Ophthalmol. 118 (1): 13–16. doi:10.1001/archopht.118.1.13. PMID 10636407. 
  11. ^ http://books.google.co.uk/books?id=HxOit-ILQlUC&pg=PA23&lpg=PA23&dq=%22Euphorbia+hedge%22&source=bl&ots=KZw2NFZhbN&sig=k9vCRUHhdgpnfSSbXIhmvhn6fzo&hl=en&sa=X&ei=pfPjU-ydC_Db7AaI04CoAg&ved=0CE0Q6AEwCA#v=onepage&q=%22Euphorbia%20hedge%22&f=false
  12. ^ a b Victor W. Steinmann & J. Mark Porter (2002). "Phylogenetic relationships in Euphorbieae (Euphorbiaceae) based on ITS and ndhF sequence data". Annals of the Missouri Botanical Garden 89 (4): 453–490. JSTOR 3298591. 
  13. ^ a b Victor W. Steinmann (2003). "The submersion of Pedilanthus into Euphorbia (Euphorbiaceae)" (PDF). Acta Botanica Mexicana 65: 45–50. 
  14. ^ a b Peter V. Bruyns, Ruvimbo J. Mapaya & Terrence J. Hedderson (2006). "A new subgeneric classification for Euphorbia (Euphorbiaceae) in southern Africa based on ITS and psbA-trnH sequence data". Taxon 55 (2): 397–420. doi:10.2307/25065587. 
  15. ^ Víctor W. Steinmann, Benjamin van Ee, Paul E. Berry & Jorge Gutiérrez (2007). "The systematic position of Cubanthus and other shrubby endemic species of Euphorbia (Euphorbiaceae) in Cuba". Anales del Jardín Botánico de Madrid 64 (2): 123–133. doi:10.3989/ajbm.2007.v64.i2.167. 
  16. ^ E. balsamifera. Flora de Canarias.
  17. ^ E. canariensis. Flora de Canarias.

16. ^ Jorgensen, L.; McKerrall, S. J.; Kuttruff, C. A.; Ungeheuer, F.; Felding, J.; Baran, P. S. (2013). "14-Step Synthesis of (+)-Ingenol from (+)-3-Carene". Science. doi:10.1126/science.1241606

Further reading[edit]

  • Buddensiek, Volker (2005): Succulent Euphorbia plus (CD-ROM). Volker Buddensiek Verlag.
  • Carter, Susan (1982): New Succulent Spiny Euphorbias from East Africa
  • Carter, Susan & Eggli, Urs (1997): The CITES Checklist of Succulent Euphorbia Taxa (Euphorbiaceae)
  • Carter, Susan & Smith, A. L. (1988): Flora of Tropical East Africa, Euphorbiaceae
  • Noltee, Frans (2001): Succulents in the wild and in cultivation, Part 2 Euphorbia to Juttadinteria (CD-ROM)
  • Eggli, Urs (ed.) (2002): Sukkulentenlexikon (Vol. 2: Zweikeimblättrige Pflanzen (Dicotyledonen)). Eugen Ulmer Verlag.
  • Everitt, J.H.; Lonard, R.L.; Little, C.R. (2007). Weeds in South Texas and Northern Mexico. Lubbock: Texas Tech University Press. ISBN 0-89672-614-2. 
  • Pritchard, Albert (2003): Introduction to the Euphorbiaceae ISBN 978-88-900511-4-2.
  • Schwartz, Herman (ed.) (1983): The Euphorbia Journal Strawberry Press, Mill Valley, California, USA
  • Singh, Meena (1994): Succulent Euphorbiaceae of India. Mrs. Meena Singh, A-162 Sector 40, NOIDA, New Delhi, India.
  • Turner, Roger (1995): Euphorbias—A Gardeners' Guide. Batsford, England.
  • Aditya Soumen [2010,Apr.]A revision of geophytic euphorbia species from India. Euphorbia World journal. Vol.6-No.1,ISSN 1746-5397
  • Pritchard albert[2010] "Monadenium" cactus & co . ISBN 978-88-95018-02-7
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Euphorbia subg. Poinsettia

Euphorbia subg. Poinsettia is a subgenus deriving from the genus Euphorbia, and is endemic to North America. It contains around 24 species, of which the best known is E. pulcherrima, the poinsettia.

This species grows wild in the mountains on the Pacific slope of Mexico, and despite many legends, no one is quite sure from which wild populations the cultivated varieties derive.[1]

This taxon was first published at genus rank under the name Poinsettia by Robert Graham in 1836.[2][3] It was demoted to a section of Euphorbia as E. sect. Poinsettia by Henri Ernest Baillon in 1858, but promoted to subgenus rank by Homer Doliver House in 1924. Recent studies have confirmed its monophyly.[4]

Its many species include:

The common name "Wild Poinsettia" is sometimes applied to two of these species.

History & Legends of the Poinsettia[edit]

The Aztecs called poinsettias "Cuetlaxochitl." During the 14th - 16th century the sap was used to control fevers and the bracts (modified leaves) were used to make a reddish dye.

Montezuma, the last of the Aztec kings, would have poinsettias brought into what now is Mexico City by caravans because poinsettias could not be grown in the high altitude.

In the 17th century, Juan Balme, a botanist, noted the poinsettia plant in his writings. The botanical name, Euphorbia pulcherrima, originated as an annotation of a herbarium specimen by the German botanist, Carl Ludwig Willdenow and was first published by Johann Friedrich Klotzsch in 1834.[5]

Joel Roberts Poinsett was the first United States Ambassador to Mexico being appointed by President John Quincy Adams in the 1820s. At the time of his appointment, Mexico was involved in a civil war. Because of his interest in botany he introduced the American elm into Mexico. During his stay in Mexico he wandered the countryside looking for new plant species. In 1828 he found a beautiful shrub with large red flowers growing next to a road. He took cuttings from the plant and brought them back to his greenhouse in South Carolina. Even though Poinsett had an outstanding career as a United States Congressman and as an ambassador he will always be remembered for introducing the poinsettia into the United States.

A nurseryman from Pennsylvania, John Bartram is credited as being the first person to sell poinsettias under its botanical name, Euphorbia pulcherrima

In the early 1900s the Ecke family of southern California grew poinsettias outdoors for use as landscape plants and as a cut flower. Eventually the family grew poinsettias in greenhouses and today is recognized as the leading producer of poinsettias in the United States.

Caring for the Poinsettia[edit]

The length of time your poinsettia will give you pleasure in your home is dependent on (1) the maturity of the plant, (2) when you buy it, and (3) how you treat the plant. With care, poinsettias should retain their beauty for weeks and some varieties will stay attractive for months.

After you have made your poinsettia selection, make sure it is wrapped properly because exposure to low temperatures even for a few minutes can damage the bracts and leaves.

Unwrap your poinsettia carefully and place in indirect light. Six hours of light daily is ideal. Keep the plant from touching cold windows.

Keep poinsettias away from warm or cold drafts from radiators, air registers or open doors and windows. Ideally poinsettias require daytime temperatures of 60 to 70 °F and night time temperatures around 55 °F. High temperatures will shorten the plant’s life. Move the plant to a cooler room at night, if possible. Check the soil daily. Be sure to punch holes in foil so water can drain into a saucer. Water when soil is dry. Allow water to drain into the saucer and discard excess water. Wilted plants will tend to drop bracts sooner.

Fertilize the poinsettia if you keep it past the holiday season. Apply a houseplant fertilizer once a month. Do not fertilize when it is in bloom.

With good care, a poinsettia will last 6–8 weeks in your home.

References[edit]

  1. ^ http://www.explorelifeonearth.org/poinsettia.html
  2. ^ R. Graham. Description of several new or rare plants... Edinburgh New Philosophical Journal 20(2): 412–413. 1836
  3. ^ Hibbert & Buist. 1839 edition. American Flower Garden Directory. p. 191
  4. ^ Park, Ki-Ryong; Jansen, Robert K. (2007). "A phylogeny of Euphorbieae subtribe Euphorbiinae". Journal of Plant Biology 50 (6): 644–49. doi:10.1007/BF03030608. 
  5. ^ zweier neuen Euphorbien aus Mexico. Allgemeine Gartenzeitung 2(4): 27–28. 1834 [1]

Poinsettia History & Legends & Care - University of Illinois Extension Poinsettia Pages

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