Editing Euphorbia (section)

== Description ==
The plants are [[annual plant|annual]], [[Biennial plant|biennial]] or [[perennial plant|perennial]] herbs, woody shrubs, or trees with a caustic, poisonous milky latex. The [[root]]s are fine or thick and fleshy or tuberous. Many species are more or less [[Succulent plant|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 [[Euphorbia neutra]] is native to the [[Caatinga]] of [[Brazil]] and Euphorbia royleana is found in the [[Himalaya]]n foothills.<ref>Karsten and Schenk , Vegetationsbilder, Volume 15 (1924)  Photoplate 6 with caption</ref> The deciduous{{citation needed|date=September 2014}} [[leaf|leaves]] may be [[Opposite (leaf)|opposite]], [[Alternate (botany)|alternate]], or in [[Whorl (botany)|whorls]]. In succulent species, the leaves are mostly small and short-lived. The [[stipule]]s are mostly small, partly transformed into [[spine (botany)|spine]]s or [[gland]]s, or missing.

===Inflorescence and fruit===
[[File:EUPHORBIA.JPG|thumb|''Euphorbia'' [[Pseudanthium|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="EPBIA">{{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}}</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 (botany)|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="EF">{{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= EF/> and may be fused into a "U" shape.<ref name= EPBIA/> 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 [[capsule (fruit)|capsule]]s, sometimes fleshy, but almost always ripening to a woody container that then splits open, sometimes [[explosive dehiscence|explosively]]. The [[seed]]s are four-angled, oval, or spherical, and some species have a [[Elaiosome|caruncle]].{{citation needed|date=August 2014}}

===Xerophytes and succulents===
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" [[xerophyte|xerophytic]]. In some cases, especially with [[storage organ|geophyte]]s, 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 [[herbivore]]s. It is white, and transparent when dry, except in ''[[Euphorbia abdelkuri|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 [[diterpene]]s. [[Triterpene]]s such as [[betulin]] and corresponding [[ester]]s 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/> 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>{{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=[[JAMA Ophthalmology|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>{{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===
[[File:Pointsetta flowers.jpg|thumb|right|Detail of poinsettia flowers and immature fruits]]
[[File:Euphorbia hybrid 11.jpg|thumb|right|upright|An old ''Euphorbia'' hybrid]]
[[File:Euphorbia obesa 222.JPG|thumb|right|''Euphorbia obesa'']]
Several spurges are grown as garden plants, among them [[poinsettia]] (''E. pulcherrima'') and the succulent ''[[Euphorbia trigona|E. trigona]]''. ''[[Euphorbia pekinensis|E. pekinensis]]'' ({{zh|c=[[wikt:大戟|大戟]]|p=dàjǐ}}) is used in [[traditional Chinese medicine]], where it is regarded as one of the [[Chinese herbology#50 fundamental herbs|50 fundamental herbs]]. Several ''Euphorbia'' species are used as food plants by the [[larva]]e 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="google">{{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 succulent]]s.<ref name="CN">{{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=CN/> 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=CN/>