Euphorbiaceae (), the spurge family, is a large family of flowering plants. In English, they are also commonly called euphorbias, which is also the name of the type genus of the family. Most spurges, such as '' Euphorbia paralias'', are

herb In general use, herbs are a widely distributed and widespread group of plants, excluding vegetables and other plants consumed for macronutrients, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal ...

s, but some, especially in the tropics, are

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

s or trees, such as ''

Hevea brasiliensis ''Hevea brasiliensis'', the Pará rubber tree, ''sharinga'' tree, seringueira, or most commonly, rubber tree or rubber plant, is a flowering plant belonging to the spurge family Euphorbiaceae Euphorbiaceae, the spurge family, is a large fami ...

''. Some, such as ''

Euphorbia canariensis ''Euphorbia canariensis'', commonly known as the Canary Island spurge, Hercules club or in Spanish ''cardón'', is a succulent member of the genus ''Euphorbia'' and family Euphorbiaceae endemic to the Canary Islands. It is the plant symbol of t ...

'', are

succulent In botany, succulent plants, also known as succulents, are plants with parts that are thickened, fleshy, and engorged, usually to retain water in arid climates or soil conditions. The word ''succulent'' comes from the Latin word ''sucus'', meani ...

and resemble

cacti A cactus (, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word ''cactus'' derives, through Latin, from the Ancient Greek ...

because of convergent evolution. This family has a cosmopolitan global distribution. The greatest diversity of species is in the tropics; however, the Euphorbiaceae also have many species in nontropical areas of all continents except Antarctica.

Description

The

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are alternate, seldom opposite, with stipules. They are mainly simple, but where compound, are always

palmate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...

, never pinnate. Stipules may be reduced to

hair Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and f ...

s, glands, or

spine Spine or spinal may refer to: Science Biology * Vertebral column, also known as the backbone * Dendritic spine, a small membranous protrusion from a neuron's dendrite * Thorns, spines, and prickles, needle-like structures in plants * Spine (zoolog ...

s, or in succulent species are sometimes absent. The plants can be

monoecious Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is conne ...

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

. The radially symmetrical flowers are unisexual, with the male and female flowers usually on the same plant. As can be expected from such a large family, a wide variety exists in the structure of the flowers. The

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s (the male organs) number from one to 10 (or even more). The female flowers are hypogynous, that is, with superior ovaries. The genera in tribe Euphorbieae, subtribe Euphorbiinae ('' Euphorbia'' and close relatives) show a highly specialized form of pseudanthium ("false flower" made up of several true flowers) called a cyathium. This is usually a small, cup-like involucre consisting of fused-together bracts and peripheral nectary glands, surrounding a ring of male flowers, each a single stamen. In the middle of the cyathium stands a female flower, a single

pistil Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils'' ...

with branched stigmas. This whole arrangement resembles a single flower. The fruit is usually a schizocarp, but sometimes a

drupe In botany, a drupe (or stone fruit) is an indehiscent fruit in which an outer fleshy part (exocarp, or skin, and mesocarp, or flesh) surrounds a single shell (the ''pit'', ''stone'', or '' pyrena'') of hardened endocarp with a seed (''kernel'') ...

. A typical schizocarp is the regma, a capsular fruit with three or more cells, each of which splits open explosively at maturity, scattering the small seeds. The family contains a large variety of phytotoxins (toxic substances produced by plants), including diterpene esters, alkaloids, and cyanogenic glycosides (e.g. root tubers of cassava). The seeds of the castor oil plant '' Ricinus communis'' contain the highly toxic carbohydrate-binding protein

ricin Ricin ( ) is a lectin (a carbohydrate-binding protein) and a highly potent toxin produced in the seeds of the castor oil plant, ''Ricinus communis''. The median lethal dose (LD50) of ricin for mice is around 22 micrograms per kilogram of body ...

. A milky latex is a characteristic of the subfamilies

Euphorbioideae The Euphorbioideae are a subfamily within the family Euphorbiaceae. See also * Taxonomy of the Euphorbiaceae Here is a full taxonomy of the family Euphorbiaceae, according to the most recent molecular research. This complex family previously ...

and

Crotonoideae The Crotonoideae (crotonoids) are a subfamily within the family Euphorbiaceae. See also * Taxonomy of the Euphorbiaceae Here is a full taxonomy of the family Euphorbiaceae, according to the most recent molecular research. This complex famil ...

, and the latex of the rubber tree ''

'' is the primary source of natural rubber. The latex is

poison Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...

ous in the Euphorbioideae, but innocuous in the Crotonoideae. White mangrove, also known as blind-your-eye mangrove latex ('' Excoecaria agallocha''), causes blistering on contact and temporary blindness if it contacts the eyes, hence its name. The latex of spurge was used as a laxative. Twenty first century molecular studies have shown that the enigmatic family Rafflesiaceae, which was only recently recognized to belong to order Malpighiales, is derived from within the Euphorbiaceae. Euphorbiaceae are monoecious and

open pollinated "Open pollination" and "open pollinated" refer to a variety of concepts in the context of the sexual reproduction of plants. Generally speaking, the term refers to plants pollinated naturally by birds, insects, wind, or human hands. True-breedi ...

and so self-incompatibility is rare - although it has been reported in the past, apparently this was in error. It is confirmed to be absent or incomplete in

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of t ...

'' Chamaesyce'' by Ehrenfeld 1976, ''

Hevea ''Hevea'' is a genus of flowering plants in the spurge family, Euphorbiaceae, with about ten members. It is also one of many names used commercially for the wood of the most economically important rubber tree, '' H. brasiliensis''. The genus is n ...

'' by Bouharmont 1962, and ''

Manihot ''Manihot'' is a genus in the diverse milkspurge family, Euphorbiaceae. It was described as a genus in 1754.Miller, Philip. 1754. Gardeners Dictionary...Abridged...fourth edition vol. 2 Species of ''Manihot'' are monoecious . . trees, shrubs a ...

'' by Jennings 1963 and George & Shifriss 1967. . .

Taxonomy

The family Euphorbiaceae is the fifth-largest flowering plant family and has about 7,500 species organised into 300 genera, 37 tribes, and three subfamilies: ''

Acalyphoideae The Acalyphoideae are a subfamily within the family Euphorbiaceae with 116 genera in 20 tribes. See also * Taxonomy of the Euphorbiaceae Here is a full taxonomy of the family Euphorbiaceae, according to the most recent molecular research. Thi ...

'', ''

'' and ''

''. Amongst the oldest fossils of the group include the permineralised fruit '' Euphorbiotheca deccanensis'' from the

Intertrappean Beds The Intertrappean Beds are a Late Cretaceous geologic formation in India. The beds are found as interbeds between Deccan Traps layers. Indeterminate theropod and pterosaur remains have been recovered from the formation, as well as dinosaur eggs ...

of India, dating to the late Maastrichtian at the end of the Cretaceous, around 66 million years ago.

Uses and toxicity

Some species of Euphorbiaceae have economic significance, such as cassava (''Manihot esculenta''), castor oil plant ('' Ricinus communis''), Barbados nut (''

Jatropha curcas ''Jatropha curcas'' is a species of flowering plant in the spurge family, Euphorbiaceae, that is native to the American tropics, most likely Mexico and Central America. It is originally native to the tropical areas of the Americas from Mexico to ...

''), and the Pará rubber tree (''Hevea brasiliensis''). Many are grown as ornamental plants, such as poinsettia ('' Euphorbia pulcherrima'') or

garden croton ''Codiaeum variegatum'' (fire croton, garden croton, or variegated croton; syn. ''Croton variegatum'' L.) is a species of plant in the genus ''Codiaeum'', which is a member of the family Euphorbiaceae. It was described by Carl Linnaeus in 1753. ...

(''Codiaeum variegatum''). Leafy spurge (''

Euphorbia esula ''Euphorbia esula'', commonly known as green spurge or leafy spurge, is a species of spurge native to central and southern Europe (north to England, the Netherlands, and Germany), and eastward through most of Asia north of the Himalaya to Korea a ...

'') and

Chinese tallow ''Triadica sebifera'' is a tree native to eastern China. It is commonly called Chinese tallow, Chinese tallowtree, Florida aspen, chicken tree, gray popcorn tree, or candleberry tree. The seeds (as well as from those of '' Triadica cochinchine ...

(''Triadica sebifera'') are

invasive Invasive may refer to: *Invasive (medical) procedure *Invasive species *Invasive observation, especially in reference to surveillance *Invasively progressive spread of disease from one organ in the body to another, especially in reference to cancer ...

weeds in North America. Seeds of the castor oil plant (''Ricinus communis'' L.) contain the extremely potent toxin, ricin. Although some species of the Euphorbiaceae have been used in traditional medicine, , there is no rigorous clinical evidence that euphorbia extracts are effective for treating any disease. There is evidence that euphol, a tetracyclic triterpene alcohol, and the main constituent of the sap of the medicinal plant ''

Euphorbia tirucalli ''Euphorbia tirucalli'' (commonly known as Indian tree spurge, naked lady, pencil tree, pencil cactus, fire stick, or milk bush) is a tree native to Africa that grows in semi-arid tropical climates. A hydrocarbon plant, it produces a poisonous l ...

'', has anti-cancer activity. Analysis of toxicological screening of the inhibitory effect and bioactivity of euphol has shown concentration-dependent cytotoxic effects on cancer cell lines, with more than a five-fold difference in the IC50 values in some cell lines. Euphol treatment had a higher selective cytotoxicity index (0.64-3.36) than temozolomide (0.11-1.13) and reduced both proliferation and cell motility. Euphol also exhibited antitumoral and antiangiogenic activity in vivo, using the chicken chorioallantoic membrane assay, with synergistic temozolomide interactions in most cell lines. In conclusion, euphol exerted in vitro and in vivo cytotoxicity against glioma cells, through several cancer pathways, including the activation of autophagy-associated cell death. Numerous Euphorbiaceae species are listed on the poisonous plant database of the US Food and Drug Administration mainly because of the toxic sap.

Phytochemistry

Phytochemicals found in Euphorbiaceae species include diterpenoids, terpenoids,

flavonoid Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...

s, alkaloids, tannins, neriifolins (also found in oleander),

cycloartenol Cycloartenol is an important triterpenoid of the sterol class which is found in plants. It is the starting point for the synthesis of almost all plant steroids, making them chemically distinct from the steroids of fungi and animals, which are, ins ...

, lectin, and

taraxerol Taraxerol is a naturally-occurring pentacyclic triterpenoid. It exists in various higher plants, including ''Taraxacum officinale'' (Asteraceae), ''Alnus glutinosa'' (Betulaceae), ''Litsea dealbata'' (Lauraceae), ''Skimmia spp.'' (Rutaceae), '' ...

, among others.

Conservation

Some species of this family are facing the risk of extinction. These include the ''Euphorbia'' species ''E. appariciana'', ''E. attastoma'', ''E. crossadenia'', and ''E. gymnoclada''.

References

External links

Marc Altenloh collection (photos)
.
International Euphorbia SocietyCactus and Succulent Society of America

Data from GRIN Taxonomy
i
L. Watson and M.J. Dallwitz (1992 onwards). The families of flowering plants: descriptions, illustrations, identification, information retrieval.
https://web.archive.org/web/20070103200438/http://delta-intkey.com/ {{Authority control Malpighiales families