Euphorbia

{{Short description|Genus of flowering plants}} {{distinguish|Euphoria}} {{For|the family commonly called "euphorbias" and "spurge family"|Euphorbiaceae{{!}}''Euphorbiaceae''}} {{Redirect-distinguish|Lathyris|Lathyrus}} {{Automatic taxobox | image = Euphorbia February 2008-2.jpg | image_caption = ''Euphorbia serrata'' | display_parents = 3 | parent_authority = Griseb. | taxon = Euphorbia | authority = L. | diversity = {{circa|2008}} species | diversity_link = List of Euphorbia species | type_species = ''Euphorbia antiquorum'' | type_species_authority = L. | subdivision_ranks = Subgenera | subdivision = ''Chamaesyce'' ''Esula'' ''Euphorbia'' ''Rhizanthium'' and see below | synonyms = {{collapsible list | *''Adenopetalum'' Klotzsch & Garcke *''Adenorima'' Raf. *''Agaloma'' Raf. *''Aklema'' Raf. *''Alectoroctonum'' Schltdl. *''Allobia'' Raf. *''Anisophyllum'' Haw. *''Anthacantha'' Lem. *''Aplarina'' Raf. *''Arthrothamnus'' Klotzsch & Garcke *''Athymalus'' Neck. *''Chamaesyce'' Gray *''Characias'' Gray *''Chylogala'' Fourr. *''Crepidaria'' Haw. *''Ctenadena'' Prokh. *''Cubanthus'' Millsp. *''Cyathophora'' Raf. *''Cystidospermum'' Prokh. *''Dactylanthes'' Haw. *''Dematra'' Raf. *''Desmonema'' Raf. *''Diadenaria'' Klotzsch & Garcke *''Dichylium'' Britton *''Diplocyathium'' Heinr.Schmidt *''Ditritra'' Raf. *''Elaeophorbia'' Stapf *''Endadenium'' L.C.Leach *''Endoisila'' Raf. *''Epurga'' Fourr. *''Esula'' (Pers.) Haw. *''Eumecanthus'' Klotzsch & Garcke *''Euphorbiastrum'' Klotzsch & Garcke *''Euphorbiodendron'' Millsp. *''Euphorbion'' St.-Lag. *''Euphorbium'' Hill *''Galarhoeus'' Haw. *''Galorhoeus'' Endl. *''Hexadenia'' Klotzsch & Garcke *''Kanopikon'' Raf. *''Keraselma'' Neck. ex Juss. *''Kobiosis'' Raf. *''Lacanthis'' Raf. *''Lepadena'' Raf. *''Leptopus'' Klotzsch & Garcke *''Lophobios'' Raf. *''Lortia'' Rendle *''Lyciopsis'' (Boiss.) Schweinf. *''Medusea'' Haw. *''Monadenium'' Pax *''Murtekias'' Raf. *''Nisomenes'' Raf. *''Peccana'' Raf. *''Pedilanthus'' Neck. ex Poit. *''Petaloma'' Raf. ex Boiss. *''Pleuradena'' Raf. *''Poinsettia'' Graham *''Pythius'' Raf. *''Sclerocyathium'' Prokh. *''Stenadenium'' Pax *''Sterigmanthe'' Klotzsch & Garcke *''Synadenium'' Boiss. *''Tirucalia'' Raf. *''Tithymalodes'' Ludw. ex Kuntze *''Tithymaloides'' Ortega *''Tithymalopsis'' Klotzsch & Garcke *''Tithymalus'' Gaertn. *''Tithymalus'' Ség. *''Tithymalus'' Mill. *''Torfasadis'' Raf. *''Treisia'' Haw. *''Trichosterigma'' Klotzsch & Garcke *''Tumalis'' Raf. *''Vallaris'' Raf. *''Ventenatia'' Tratt. *''Xamesike'' Raf. *''Zalitea'' Raf. *''Zygophyllidium'' Small }} | synonyms_ref =<ref>{{cite web |url=http://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:327729-2#synonyms |title=Euphorbia L. |author= |date=2017 |website=Plants of the World Online |publisher=Board of Trustees of the Royal Botanic Gardens, Kew |access-date=7 July 2020 }}</ref> }} [[File:Euphorbia dendroides3-Corsica~2011 04 30.jpg|thumb|right|''Euphorbia'' as a small tree: ''Euphorbia dendroides'']]

'''''Euphorbia''''' is a large and diverse genus of flowering plants, commonly called '''spurge''', in the family Euphorbiaceae.

Euphorbias range from tiny annual plants to large and long-lived trees,<ref name="Fine Gardening">{{Cite news |title=Euphorbia |work=Fine Gardening |publisher=The Taunton Press, Inc. |url=https://www.finegardening.com/genus/euphorbia}}</ref> with perhaps the tallest being ''Euphorbia ampliphylla'' at {{convert|30|m|ft|0|abbr=on}} or more.<ref>{{cite book | last1= Brenan | first1= J.P.M. | last2= Greenway | first2= P.J. | date= 1949 | title= Check-lists of the Forest Trees and Shrubs of the British Empire #5 - Tanganyika Territory | location= Oxford, England | publisher= Imperial Forestry Institute | page= 214 (part 2) }}</ref><ref>{{cite journal | last= Hargreaves | first= Bruce | date=n.d. | title= Euphorbia ingens in Malawi...etc. | journal= Euphorbia Journal | volume= 7 | page= 78 plus diagram p. 63}}</ref> The genus has roughly 2,000 members,<ref name="Kew World Checklist">{{cite web|url=http://apps.kew.org/wcsp/reportbuilder.do|title=World Checklist of Selected Plant Families (WCSP)|work=Kew Science|publisher=Royal Botanic Gardens, Kew|access-date=16 Apr 2011}}</ref><ref name="Planetary Biodiversity Inventory-2022">{{Cite web |title=Euphorbia PBI - Project Description |url=http://www.euphorbiaceae.org/pages/project.html |access-date=1 Feb 2019 |publisher=Planetary Biodiversity Inventory (PBI) |archive-date=31 March 2022 |archive-url=https://web.archive.org/web/20220331004831/https://euphorbiaceae.org/pages/project.html |url-status=dead }}</ref> making it one of the largest genera of flowering plants.<ref name="Stebbins-1976">{{Cite journal|vauthors=Stebbins GL, Hoogland RD|year=1976|title=Species diversity, ecology and evolution in a primitive Angiosperm genus:Hibbertia (Dilleniaceae)|journal=Plant Syst. Evol.|volume=125|issue=3|pages=139–154|doi=10.1007/BF00986147|bibcode=1976PSyEv.125..139S |s2cid=27820065}}</ref><ref name="Houzz-2010">{{Cite web|url=http://www.houzz.com/discussions/1795347/euphorbia-botany-lesson|title=Euphorbia botany lesson|date=30 Jun 2010|website=Houzz|access-date=1 Feb 2019}}</ref> It also has one of the largest ranges of chromosome counts, along with ''Rumex'' and ''Senecio''.<ref name="Stebbins-1976"/> ''Euphorbia antiquorum'' is the type species for the genus ''Euphorbia''.<ref>{{cite book|title=Dicotyledons|last=Carter|first=S.|publisher=Springer|year=2002|isbn=978-3-540-41966-2|editor-last=Eggli|editor-first=U.|series=Illustrated Handbook of Succulent Plants|volume=5|pages=102|chapter=''Euphorbia''|name-list-style=vanc|chapter-url=https://books.google.com/books?id=ffBRAyZLuh0C&pg=PA102}}</ref> It was first described by Carl Linnaeus in 1753 in ''Species Plantarum''.

Some euphorbias are widely available commercially, such as poinsettias at Christmas. Some are commonly cultivated as ornamentals, or collected and highly valued for the aesthetic appearance of their unique floral structures, such as the crown of thorns plant (''Euphorbia milii''). Succulent euphorbias from the deserts of Southern Africa and Madagascar have evolved physical characteristics and forms similar to cacti of North and South America, so they are often incorrectly referred to as cacti.<ref>{{Cite web |title=Cacti or Not? Many succulents look like cacti, but are not |url=http://cactiguide.com/cactiornot/ |access-date=1 Feb 2019 |website=CactiGuide.com}}</ref> Some are used as ornamentals in landscaping, because of beautiful or striking overall forms, and drought and heat tolerance.<ref name="Planetary Biodiversity Inventory-2022" /><ref name="Fine Gardening" />

Euphorbia all share the feature of having a poisonous, latex-like sap and unique floral structures.<ref name="Planetary Biodiversity Inventory-2022" /> When viewed as a whole, the head of flowers looks like a single flower (a pseudanthium).<ref name="Planetary Biodiversity Inventory-2022" /> It has a unique kind of pseudanthium, called a cyathium, where each flower in the head is reduced to its barest essential part needed for sexual reproduction.<ref name="Planetary Biodiversity Inventory-2022" /> The individual flowers are either male or female, with the male flowers reduced to only the stamen, and the females to the pistil.<ref name="Planetary Biodiversity Inventory-2022" /> These flowers have no sepals, petals, or other parts that are typical of flowers in other kinds of plants.<ref name="Planetary Biodiversity Inventory-2022" /> Structures supporting the flower head and other structures underneath have evolved to attract pollinators with nectar, and with shapes and colors that function in a way petals and other flower parts do in other flowers. It is the only genus of plants that has all three kinds of photosynthesis, CAM, C3 and C4.<ref name="Planetary Biodiversity Inventory-2022" />

==Etymology== 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 Euphorbos, the Greek physician of King Juba II of Numidia and Mauretania (52–50 BC – 23 AD), who married the daughter of Anthony and Cleopatra.<ref name="Dale-1986">{{cite book|title=Flowering Plants of the Santa Monica Mountains|last=Dale|first=Nancy|publisher=California Native Plant Society|year=1986|isbn=978-0-88496-239-7|page=107|name-list-style=vanc}}</ref> Juba was a prolific writer on various subjects, including natural history. Euphorbos wrote that one of the cactus-like euphorbias (now called ''Euphorbia obtusifolia'' ssp. ''regis-jubae'') was used as a powerful laxative.<ref name="Dale-1986"/> In 12 BC, Juba named this plant after his physician Euphorbos, as Augustus Caesar had dedicated a statue to the brother of Euphorbos, Antonius Musa, who was the personal physician of Augustus.<ref name="Dale-1986"/> In 1753, botanist and taxonomist Carl Linnaeus assigned the name ''Euphorbia'' to the entire genus in the physician's honor.<ref>{{cite book|title=Species Plantarum|title-link=Species Plantarum|last=Linnaeus|first=Carl|year=1753|edition=1st|page=450|chapter=''Euphorbia''|name-list-style=vanc|author-link=Carl Linnaeus}}</ref>

== Description == The plants are annual, biennial or perennial herbs, woody shrubs, or trees with a caustic, poisonous milky 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, and often winged, {{convert|15|–|91|cm|in|round=0.5|abbr=on}} tall. The succulent trees and large shrubs are mostly confined to southern and eastern Africa, but others are found elsewhere. For example, ''Euphorbia neutra'' is native to the Caatinga of Brazil and ''Euphorbia royleana'' is found in the Himalayan foothills.<ref>Karsten and Schenk, Vegetationsbilder, Volume 15 (1924) Photoplate 6 with caption</ref> The deciduous{{citation needed|date=September 2014}} leaves may be 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.

===Inflorescence and fruit=== [[File:EUPHORBIA.JPG|thumb|''Euphorbia'' false-flower]] {{More citations needed section|date=May 2016}}Like all members of the family Euphorbiaceae, spurges have unisexual flowers.

In ''Euphorbia'', flowers occur in a head, called the cyathium (plural cyathia). Each male or female flower in the cyathium head has only its essential sexual part, in males the stamen, and in females the pistil. The flowers do not have sepals, petals, or nectar to attract pollinators, although other nonflower parts of the plant have an appearance and nectar glands with similar roles. Euphorbias are the only plants known to have this kind of flower head.<ref name="Planetary Biodiversity Inventory-2009 (PBI)">{{Cite web|url=http://www.euphorbiaceae.org/pages/about_euphorbia.html|title=About the genus ''Euphorbia''|publisher=Planetary Biodiversity Inventory (PBI)|access-date=1 Feb 2019|archive-date=28 March 2009|archive-url=https://web.archive.org/web/20090328121630/http://www.euphorbiaceae.org/pages/about_euphorbia.html|url-status=dead}}</ref>

Nectar glands and nectar that attract pollinators are held in the involucre, a cup-like part below and supporting the cyathium head. The "involucre" in the genus ''Euphorbia'' is not to be confused with the "involucre" in family Asteraceae members, which is a collection of bracts called phyllaries, which surround and encase the unopened flower head, then support the receptacle under it after the flower head opens.

The involucre is above and supported by bract-like modified leaf structures (usually in pairs){{citation needed|date=August 2014}} called cyathophylls', or cyathial leaves. The cyathophyll often has a superficial appearance of being petals of a flower.

''Euphorbia'' flowers are tiny, and the variation attracting different pollinators, with different forms and colors occurs, in the cyathium, involucre, cyathophyll, or additional parts such as glands that attached to these.

The collection of many flowers may be shaped and arranged to appear collectively as a single individual flower, sometimes called a pseudanthium in the Asteraceae, and also in ''Euphorbia''.

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.{{citation needed|date=August 2014}}

The female flowers reduced to a single pistil usually split into three parts, often with two stigmas at each tip.{{citation needed|date=August 2014}} Male flowers often have anthers in twos.{{citation needed|date=August 2014}} Nectar glands usually occur in fives,<ref name="Stein-2011">{{Cite web|url=https://www.davesgarden.com/guides/articles/|title=Euphorbia "Flowers," an introduction to the amazing Cyathia|last=Stein|first=G.|date=22 Apr 2011|website=Dave's Garden|access-date=1 Feb 2019}}</ref> may be as few as one,<ref name="Stein-2011"/> and may be fused into a "U" shape.<ref name="Planetary Biodiversity Inventory-2009 (PBI)"/> The cyathophylls often occur in twos, are leaf-like, and may be showy and brightly coloured and attractive to pollinators, or be reduced to barely visible tiny scales.{{citation needed|date=August 2014}}

The fruits are three- or rarely two-compartment capsules, sometimes fleshy, but almost always ripening to a woody container that then splits open, sometimes explosively. The seeds are four-angled, oval, or spherical, and some species have a caruncle.{{citation needed|date=August 2014}}

===Xerophytes and succulents=== [[File:Euphorbia turbiniformis.jpg|thumb|250x250px|''Euphorbia turbiniformis'', a rare succulent ''Euphorbia'' from Somalia]] In the genus ''Euphorbia'', succulence in the species has often evolved divergently and to differing degrees. Sometimes, it is difficult to decide, and 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.

=== Irritants === The milky sap of spurges (called "latex") evolved as a deterrent to herbivores. It is white, and transparent 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.<ref>{{Cite web|url=http://www.euphorbia.de/res_liste.htm|title=Research into euphorbia latex and irritant ingredients|last=Hodgkiss|first=RJ|website=www.euphorbia.de|access-date=2 Nov 2013}}</ref> In contact with mucous membranes (eyes, nose, mouth), the latex can produce extremely painful inflammation. The sap has also been known to cause mild to extreme Keratouveitis, which affects vision.<ref name="Basak-2009"/> Therefore, spurges should be handled with caution and kept away from children and pets. Wearing eye protection while working in close contact with ''Euphorbia'' is advised.<ref name="Basak-2009">{{Cite journal|last1=Basak |first1=Samar K. |last2=Bakshi |first2=Partho K. |last3=Basu |first3=Sabitabrata |last4=Basak |first4=Soham |date=2009 |title=Keratouveitis caused by Euphorbia plant sap |journal=Indian Journal of Ophthalmology|volume=57|issue=4 |pages=311–313 |doi=10.4103/0301-4738.53060 |issn=0301-4738 |pmc=2712704 |pmid=19574703 |doi-access=free }}</ref> Latex on skin should be washed off immediately and thoroughly. Congealed latex is insoluble in water, but can be removed with an emulsifier such as 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.<ref>{{cite journal|vauthors=Eke T, Al-Husainy S, Raynor MK|year=2000 |title=The spectrum of ocular inflammation caused by ''Euphorbia'' plant sap |journal=Arch. Ophthalmol. |volume=118|issue=1|pages=13–16 |doi=10.1001/archopht.118.1.13 |pmid=10636407 |doi-access=free}}</ref>

The poisonous qualities were well known: in the Ethiopian ''Kebra Nagast'', the serpent king Arwe is killed with juice from the ''Euphorbia''.<ref name="Manzo-2014">{{cite journal |url=https://journals.sub.uni-hamburg.de/aethiopica/article/view/737/823 |title=Snakes and Sacrifices: Tentative Insights into the Pre-Christian Ethiopian Religion |journal=Aethiopica |volume=17 |year=2014 |pages=7–24 |issn=2194-4024 |first=Andrea |last=Manzo|doi=10.15460/aethiopica.17.1.737 |doi-access=free }}</ref>

===Uses=== thumb|right|Detail of poinsettia flowers and immature fruits thumb|right|upright|An old ''Euphorbia'' hybrid thumb|right|''Euphorbia obesa'' Several spurges are grown as garden plants, among them poinsettia (''E. pulcherrima'') and the succulent ''E. trigona''. ''E. pekinensis'' ({{lang-zh|c=大戟|p=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 hawkmoths (''Hyles euphorbiae'' and ''Hyles tithymali''), as well as the giant leopard moth.

Ingenol mebutate, a drug used to treat actinic keratosis, is a diterpenoid found in ''Euphorbia peplus''.

Euphorbias are often used as hedging plants in many parts of Africa.<ref name="Adamson-2011">{{cite book|url=https://books.google.com/books?id=HxOit-ILQlUC|title=Born Free: The Full Story|last=Adamson|first=J.|date=2011|publisher=Pan Macmillan|isbn=9780330536745|pages=23|name-list-style=vanc|access-date=6 Oct 2014}}</ref>

===Misidentification as cacti=== [[File:Euphorbia milii - flower view01.jpg|thumb|right|''Euphorbia milii'']] Among laypeople, ''Euphorbia'' species are among the plant taxa most commonly confused with cacti, especially the stem succulents.<ref name="Beaulieu-2018">{{Cite web|url=https://www.thespruce.com/difference-between-cacti-and-succulents-3976741|title=Do You Know the Difference Between Cacti and Succulents?|last=Beaulieu|first=D|date=21 Oct 2018|website=The Spruce|publisher=Dotdash|access-date=1 Feb 2019}}</ref> Euphorbias secrete a sticky, milky-white fluid with latex, but cacti do not.<ref name="Beaulieu-2018"/> Individual flowers of euphorbias are usually tiny and nondescript (although structures around the individual flowers may not be), without petals and sepals, unlike cacti, which often have fantastically showy flowers.<ref name="Beaulieu-2018"/>

== Systematics and taxonomy == The present taxon "''Euphorbia''" corresponds to its own former subtribe, the Euphorbiinae.{{citation needed|date=August 2014}} It has over 2000 species.<ref name="Planetary Biodiversity Inventory-2022"/> Morphological description using the presence of a cyathium (see section above) is consistent with nuclear and chloroplast DNA sequence data in testing of about 10% of its members. This testing supports inclusion of formerly other genera as being best placed in this single genus, including ''Chamaesyce, Monadenium, Pedilanthus'', and poinsettia (''E. pulcherrima'').

Genetic tests have shown that similar flower head structures or forms within the genus, might not mean close ancestry within the genus. The genetic data show that within the genus, convergent evolution of inflorescence structures may be from ancestral subunits that are not related. So using morphology within the genus becomes problematic for further subgeneric grouping. As stated on the Euphorbia Planetary Biodiversity Inventory project webpage:<ref name="Planetary Biodiversity Inventory-2022"/> {{blockquote|Previous morphologically based delimitations of subgenera or sections within the genus should not be taken at face value. The genus is in fact rife with striking examples of morphological convergence in cyathial and vegetative features, which justifies a global approach to studying the genus to obtain a proper phylogenetic understanding of the whole group.... The bottom line is that a number of clades have been placed inside or outside of Euphorbia at different times... few of the subgeneric circumscriptions hold up under DNA sequence analysis.}}

According to a 2002 publication on studies of DNA sequence data,<ref name="Steinmann-2002">{{cite journal|vauthors=Steinmann VW, Porter JM|year=2002|title=Phylogenetic relationships in Euphorbieae (Euphorbiaceae) based on ITS and ndhF sequence data|journal=Ann. Missouri Bot. Gard.|volume=89|issue=4|pages=453–490|jstor=3298591|doi=10.2307/3298591|bibcode=2002AnMBG..89..453S |url=https://www.biodiversitylibrary.org/part/16388}}</ref><ref name="Steinmann-2003">{{Cite journal|vauthors=Steinmann VW|date=2003|title=The submersion of Pedilanthus into Euphorbia (Euphorbiaceae)|journal=Acta Botanica Mexicana|language=en|issue=65|pages=45–50|doi=10.21829/abm65.2003.961|issn=2448-7589|doi-access=free}}</ref><ref name="Bruyns-2006">{{cite journal|vauthors=Bruyns PV, Mapaya RJ, Hedderson TJ|year=2006|title=A new subgeneric classification for ''Euphorbia'' (Euphorbiaceae) in southern Africa based on ITS and ''psbA-trnH'' sequence data|journal=Taxon|volume=55|issue=2|pages=397–420|doi=10.2307/25065587|jstor=25065587|bibcode=2006Taxon..55..397B }}</ref> 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'',<ref name="Steinmann-2007">{{cite journal|vauthors=Steinmann VW, van Ee B, Berry PE, Gutiérrez J|year=2007|title=The systematic position of ''Cubanthus'' and other shrubby endemic species of ''Euphorbia'' (Euphorbiaceae) in Cuba|journal=Anales Jard. Bot. Madrid|volume=64|issue=2|pages=123–133|doi=10.3989/ajbm.2007.v64.i2.167|doi-access=free|bibcode=2007AJBM...64..123S }}</ref> ''Elaeophorbia'', ''Endadenium'', ''Monadenium'', ''Synadenium'', and ''Pedilanthus'' were transferred to ''Euphorbia''. The entire subtribe Euphorbiinae now consists solely of the genus ''Euphorbia''. ''Euphorbia'' is now subdivided into four subgenera: ''Athymalus'', ''Chamaesyce'', ''Esula'' and ''Euphorbia''.<ref name="Dorsey"/><ref name="Yang"/>

=== Selected species === See List of ''Euphorbia'' species for complete list.

* ''Euphorbia albomarginata'' – rattlesnake weed, white-margined sandmat * ''Euphorbia amygdaloides'' – wood spurge * ''Euphorbia antisyphilitica'' – candelilla * ''Euphorbia balsamifera'' – sweet tabaiba (Canary Islands)<ref>{{Cite web|url=http://www.floradecanarias.com/euphorbia_balsamifera.html|title=''Euphorbia balsamifera''|website=Flora de Canarias|access-date=1 Feb 2019}}</ref> * ''Euphorbia bulbispina'' * ''Euphorbia caducifolia'' – leafless milk hedge<ref>{{cite web |url=https://www.flowersofindia.net/catalog/slides/Leafless%20Milk%20Hedge.html |title=Leafless milk hedge |publisher=Flowers of India |accessdate=29 September 2021}}</ref> * ''Euphorbia canariensis'' – Canary Island spurge, Hercules club (Canary Islands)<ref>{{Cite web|url=http://www.floradecanarias.com/euphorbia_canariensis.html|title=''Euphorbia canariensis''|website=Flora de Canarias|access-date=1 Feb 2019}}</ref> * ''Euphorbia candelabrum'' – candelabra tree of East Africa * ''Euphorbia caput-medusae'' – Medusa's head (South Africa) * ''Euphorbia ceratocarpa'' – (Sicily and southern Italy) * ''Euphorbia characias'' – Mediterranean spurge * ''Euphorbia coerulescens'' - blue euphorbia<ref>[https://www.cactus-art.biz/schede/EUPHORBIA/Euphorbia_coerulescens/Euphorbia_coerulescens/Euphorbia_coerulescens.htm Euphorbia coerulescens]</ref> * ''Euphorbia cotinifolia'' – copper tree * ''Euphorbia cyathophora'' – fire-on-the-mountain * ''Euphorbia cyparissias'' – Cypress spurge * ''Euphorbia decidua'' * ''Euphorbia dendroides'' – tree spurge * ''Euphorbia epithymoides'' – cushion spurge * ''Euphorbia esula'' – leafy spurge * ''Euphorbia franckiana'' * ''Euphorbia fulgens'' – scarlet plume * ''Euphorbia grantii'' – African milk bush * ''Euphorbia gregersenii'' – Gregersen's spurge * ''Euphorbia griffithii'' – Griffith's spurge * ''Euphorbia helioscopia'' – sun spurge * ''Euphorbia heterophylla'' – painted euphorbia, desert poinsettia, fireplant, paint leaf, kaliko * ''Euphorbia hirta'' – asthma-plant * ''Euphorbia hispida'' * ''Euphorbia horrida'' – African milk barrel * ''Euphorbia ingens'' – candelabra tree * ''Euphorbia labatii'' * ''Euphorbia lactea'' – mottled spurge, frilled fan, elkhorn * ''Euphorbia lathyris'' – caper spurge, paper spurge, gopher spurge, gopher plant, mole plant * ''Euphorbia leuconeura'' – Madagascar jewel * ''Euphorbia maculata'' – spotted spurge, prostrate spurge * ''Euphorbia magdalenae'' * ''Euphorbia marginata'' – snow on the mountain * ''Euphorbia mammillaris'' * ''Euphorbia maritae'' * ''Euphorbia milii'' – crown-of-thorns, Christ plant * ''Euphorbia misera'' – cliff spurge, Baja California, Southern California * ''Euphorbia myrsinites'' – myrtle spurge, creeping spurge, donkey tail * ''Euphorbia nivulia'' – leafy milk hedge<ref>{{cite web |url=https://www.flowersofindia.net/catalog/slides/Leafy%20Milk%20Hedge.html |title=Leafy milk hedge |publisher=Flowers of India |accessdate=29 September 2021}}</ref> * ''Euphorbia obesa'' * ''Euphorbia paralias'' – sea spurge * ''Euphorbia pekinensis'' – Peking spurge * ''Euphorbia peplis'' – purple spurge * ''Euphorbia peplus'' – petty spurge * Euphorbia piscidermis – fish skin euphorbia * ''Euphorbia polychroma'' – bonfire * ''Euphorbia psammogeton'' – sand spurge * ''Euphorbia pulcherrima'' – poinsettia, Mexican flame leaf, Christmas star, winter rose, ''noche buena'', ''lalupatae'', ''pascua'', ''Atatürk çiçeği'' (Turkish) * ''Euphorbia purpurea'' – Darlington's glade spurge, glade spurge, or purple spurge * ''Euphorbia resinifera'' – resin spurge * ''Euphorbia rigida'' – gopher spurge, upright myrtle spurge * ''Euphorbia serrata'' – serrated spurge, sawtooth spurge * ''Euphorbia tirucalli'' – Indian tree spurge, milk bush, pencil tree, firestick * ''Euphorbia tithymaloides'' – devil's backbone, redbird cactus, ''cimora misha'' (Peru) * ''Euphorbia trigona'' – African milk tree, cathedral cactus, Abyssinian euphorbia * ''Euphorbia tuberosa'' * ''Euphorbia virosa'' – gifboom or poison tree

===Hybrids=== ''Euphorbia'' has been extensively hybridised for garden use, with many cultivars available commercially. Moreover, some hybrid plants have been found growing in the wild, for instance ''E.'' × ''martini'' Rouy,<ref>{{cite web|url=http://wcsp.science.kew.org/namedetail.do?name_id=80791|title=World Checklist of Selected Plant Families (WCSP) - ''Euphorbia'' × ''martini'' Rouy, Ill. Pl. Eur. 13: 107 (1900)|website=Kew Science|publisher=Royal Botanic Gardens, Kew|access-date=26 Feb 2018}}</ref> a cross of ''E. amygdaloides'' × ''E. characias'' subsp. ''characias'', found in southern France.

=== Subgenera === [[Image:Euphorbiinae tree.png|thumb|Simplified diagram of relations in subtribe Euphorbiinae, 2006<ref name="Bruyns-2006"/>]]

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,<ref name="Steinmann-2002"/><ref name="Steinmann-2003" /><ref name="Bruyns-2006"/> ''Euphorbia'' can be divided into four subgenera, each containing several sections and groups. Of these, subgenus ''Esula'' is the most basal. The subgenera ''Chamaesyce'' and ''Euphorbia'' are probably sister taxa, but very closely related to subgenus ''Athymalus'' (formerly ''Rhizanthium''<ref name="Yang"/>). Extensive xeromorph adaptations in all probability evolved several times;<ref>{{Cite journal |last1=Horn |first1=James W. |last2=van Ee |first2=Benjamin W. |last3=Morawetz |first3=Jeffery J. |last4=Riina |first4=Ricarda |last5=Steinmann |first5=Victor W. |last6=Berry |first6=Paul E. |last7=Wurdack |first7=Kenneth J. |date=May 2012 |title=Phylogenetics and the evolution of major structural characters in the giant genus Euphorbia L. (Euphorbiaceae) |journal=Molecular Phylogenetics and Evolution |volume=63 |issue=2 |pages=305–326 |doi=10.1016/j.ympev.2011.12.022 |issn=1095-9513 |pmid=22273597|bibcode=2012MolPE..63..305H |hdl=10261/169091 |s2cid=22055432 |hdl-access=free }}</ref> it is not known if the common ancestor of the cactus-like ''Athymalus'' and ''Euphorbia'' lineages had been 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.

* '''''Esula'''''<ref>{{Cite journal |last1=Riina |first1=Ricarda |last2=Peirson |first2=Jess A. |last3=Geltman |first3=Dmitry V. |last4=Molero |first4=Julián |last5=Frajman |first5=Božo |last6=Pahlevani |first6=Amirhossein |last7=Barres |first7=Laia |last8=Morawetz |first8=Jeffery J. |last9=Salmaki |first9=Yasaman |last10=Zarre |first10=Shahin |last11=Kryukov |first11=Aleksey |last12=Bruyns |first12=Peter V. |last13=Berry |first13=Paul E. |date=2013-04-20 |title=A worldwide molecular phylogeny and classification of the leafy spurges, Euphorbia subgenus Esula (Euphorbiaceae) |url=http://doi.wiley.com/10.12705/622.3 |journal=Taxon |language=en |volume=62 |issue=2 |pages=316–342 |doi=10.12705/622.3|bibcode=2013Taxon..62..316R |url-access=subscription }}</ref> <gallery> Image:Light green flowers.jpg|Wood spurge ''Euphorbia amygdaloides'' Image:Zypressenwolfsmilch01.jpg|Cypress spurge ''Euphorbia cyparissias'' Image:Euphorbia esula.jpeg|Leafy spurge ''Euphorbia esula'' Image:Euphorbia myrsinites.JPG|Myrtle spurge ''Euphorbia myrsinites'' </gallery>

* '''''Athymalus''''' <gallery> Image:Euphorbia ferox2 ies.jpg|''Euphorbia ferox'' Image:E flanaganii ies.jpg|''Euphorbia flanaganii'' Image:E meloformis valida ies.jpg|''Euphorbia meloformis'' ssp. ''valida'' Image:E obesa symmetrica ies.jpg|''Euphorbia obesa'' ssp. ''symmetrica'' </gallery>

* '''''Chamaesyce'''''<ref name="Yang">{{Cite journal |last1=Yang |first1=Ya |last2=Riina |first2=Ricarda |last3=Morawetz |first3=Jeffery J. |last4=Haevermans |first4=Thomas |last5=Aubriot |first5=Xavier |last6=Berry |first6=Paul E. |date=August 2012 |title=Molecular phylogenetics and classification of Euphorbia subgenus Chamaesyce (Euphorbiaceae) |url=https://onlinelibrary.wiley.com/doi/10.1002/tax.614005 |journal=Taxon |language=en |volume=61 |issue=4 |pages=764–789 |doi=10.1002/tax.614005|bibcode=2012Taxon..61..764Y |hdl=2027.42/146846 |hdl-access=free }}</ref> <gallery> Image:Chamaesyce cyathia.jpg|''Euphorbia celastroides'' Image:Euphorbia heterophylla with cyathia.JPG|Painted euphorbia ''Euphorbia heterophylla'' Image:E pulcherrima ies.jpg|Poinsettia ''Euphorbia pulcherrima'' Image:E rivae ies.jpg|''Euphorbia rivae'' </gallery>

* '''''Euphorbia'''''<ref name="Dorsey">{{Cite journal |last1=Dorsey |first1=Brian L. |last2=Haevermans |first2=Thomas |last3=Aubriot |first3=Xavier |last4=Morawetz |first4=Jeffery J. |last5=Riina |first5=Ricarda |last6=Steinmann |first6=Victor W. |last7=Berry |first7=Paul E. |date=2013-04-20 |title=Phylogenetics, morphological evolution, and classification of Euphorbia subgenus Euphorbia |url=http://doi.wiley.com/10.12705/622.1 |journal=Taxon |language=en |volume=62 |issue=2 |pages=291–315 |doi=10.12705/622.1|bibcode=2013Taxon..62..291D |hdl=2027.42/146962 |s2cid=87352157 |hdl-access=free }}</ref> <gallery> Image:E actinoclada ies.jpg|''Euphorbia actinoclada'' Image:E attastoma attastoma ies.jpg|''Euphorbia attastoma'' var. ''attastoma'' Image:E confinalis rhodesica ies.jpg|''Euphorbia confinalis'' ssp. ''rhodesica'' Image:E lupulina ies.jpg|''Euphorbia lupulina'' Image:Euphorbia neriifolia Hong Kong.jpg|''Euphorbia neriifolia'' </gallery>

== See also == * ''Euphorbia'' subg. ''Poinsettia''

==References== {{Reflist|32em}}

==Further reading== {{refbegin}} *{{Cite book|url=http://www.cactus-mall.com/cdrom/euphorbia.html|title=Succulent Euphorbia plus|last=Buddensiek|first=Volker|publisher=Volker Buddensiek Verlag|year=2005|type=CD-ROM|name-list-style=vanc|archive-date=2017-07-27|access-date=2019-02-01|archive-url=https://web.archive.org/web/20170727075601/http://www.cactus-mall.com/cdrom/euphorbia.html|url-status=dead}} *{{Cite book|title=New Succulent Spiny Euphorbias from East Africa|last=Carter|first=Susan|publisher=Royal Botanic Gardens, Kew|year=1982|isbn=9781878762726|series=Hooker's Icones plantarum|name-list-style=vanc}} *{{Cite book|title=The CITES Checklist of Succulent Euphorbia Taxa (Euphorbiaceae)|vauthors=Carter S, Eggli U|publisher=German Federal Agency for Nature Conservation|year=1997|isbn=9783896246097|location=Germany}} *{{Cite book|title=Flora of Tropical East Africa|vauthors=Carter S, Smith AL|publisher=Royal Botanic Gardens, Kew|year=1988|chapter=Euphorbiaceae|title-link=Flora of Tropical East Africa}} *{{Cite book|url=http://www.cactus-mall.com/cdrom/fn.html|title=Succulents in the wild and in cultivation, Part 2 Euphorbia to Juttadinteria|last=Noltee|first=Frans|year=2001|type=CD-ROM|name-list-style=vanc|archive-date=2019-02-02|access-date=2019-02-01|archive-url=https://web.archive.org/web/20190202042220/http://www.cactus-mall.com/cdrom/fn.html|url-status=dead}} *{{Cite book|title=Sukkulenten-Lexikon|publisher=Eugen Ulmer Verlag|year=2002|isbn=9783800139156|veditors=Urs E|volume=2: Zweikeimblättrige Pflanzen (Dicotyledonen)|language=de}} *{{cite journal|title=Euphorbia grandicornis Sap Keratouveitis: A Case Report|journal=Case Rep. Ophthalmol.|vauthors=Gómez-Valcárcel M, Fuentes-Páez G|year=2016|volume=7|issue=1|pages=125–129|doi=10.1159/000444438|pmid=27293414|pmc=4899636}} *{{Cite book|last1=Everitt|first1=J.H.|last2=Lonard|first2=R.L.|last3=Little|first3=C.R.|publisher=Texas Tech University Press|year=2007|title=Weeds in South Texas and Northern Mexico|location=Lubbock|name-list-style=vanc|isbn=9780896726147}} *{{Cite book|title=Introduction to the Euphorbiaceae|last=Pritchard|first=Albert|publisher=Cactus & Co.|year=2003|isbn=9788890051142|language=it|name-list-style=vanc}} *{{Cite book|title=The Euphorbia Journal|publisher=Strawberry Press|year=1983|veditors=Schwartz H|location=Mill Valley, CA}} *{{Cite book|title=Succulent Euphorbiaceae of India|vauthors=Singh M|publisher=Meena Singh (self published)|year=1994|location=India|asin=B004PFR2G6}} *{{Cite book|title=Euphorbias: A Gardeners' Guide|vauthors=Turner R|publisher=Timber Press, Inc.|year=1995|isbn=9780881923308|location=Bastford|author-link=Roger Turner (garden designer)}} *{{Cite journal|vauthors=Soumen A|date=2010|title=A revision of geophytic euphorbia species from India|url=https://www.euphorbia-international.org/journal/pdf_files/EW6-1-sample.pdf|journal=Euphorbia World|volume=6|issue=1|pages=18–21|issn=1746-5397|archive-date=2020-12-02|access-date=2019-02-01|archive-url=https://web.archive.org/web/20201202052654/https://www.euphorbia-international.org/journal/pdf_files/EW6-1-sample.pdf|url-status=dead}} *{{Cite book|title=Monadenium|vauthors=Pritchard A|publisher=Cactus & Co.|year=2010|isbn=9788895018027|location=Venegono Superiore}} {{refend}}

==External links== * {{commons category-inline}} * {{cite EB1911|wstitle=Euphorbia |volume=9 |short=x}} * [http://www.euphorbia-international.org/ International Euphorbia Society] * [http://www.ipni.org/ipni/plantsearch?request_type=search&output_format=query&ret_defaults=on IPNI]

Category:Euphorbia Category:Medicinal plants Category:Euphorbiaceae genera Category:Botanical taxa named by Carl Linnaeus