Euphorbiaceae (), the spurge family, is a large family of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s. 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 ''Euphorbia paralias'', the Sea Spurge, is a species of flowering plant in the family Euphorbiaceae, native to Europe, northern Africa and western Asia. The species is widely naturalised in Australia. It invades coastal areas, displacing local ...

'', are

herb Herbs are a widely distributed and widespread group of plants, excluding vegetables, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal purposes, or for fragrances. Culinary use typically distingu ...

s, but some, especially in the

tropics The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

, are

shrub A shrub or 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 by their multiple ...

s or

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

s, 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, originally native to the Amazon basin, but is now p ...

''. 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 th ...

'', 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 (: cacti, cactuses, or less commonly, cactus) is a member of the plant family Cactaceae (), a family of the order Caryophyllales comprising about 127 genera with some 1,750 known species. The word ''cactus'' derives, through Latin, ...

because of

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...

. 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 Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

Description

The

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

are alternate, seldom opposite, with

stipule In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole (botany), petiole). They are primarily found among dicots and rare among monocots. Stipules are considered part ...

s. They are mainly simple, but where compound, are always

palmate The following terms are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (that is, the leaf blade or 'lamina' is undivided) or compound (that is, the leaf blade is divided into two or more leaflets ...

, never

pinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and ...

. 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 ...

s, glands, or

spine Spine or spinal may refer to: Science Biology * Spinal 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 (zoology), ...

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 comparable with gynomonoecy, andromonoecy and trimonoecy, and contras ...

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

. The radially symmetrical

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s 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 (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s (the male organs) number from one to 10 (or even more). The female flowers are

hypogynous In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds the ovule(s) and is located above or below or at the point of connection with the ba ...

, that is, with superior

ovaries The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are endocr ...

. The genera in tribe

Euphorbieae Euphorbieae is a tribe of flowering plants of the family Euphorbiaceae. It comprises 3 subtribes and 5 genera. The 3 sub tribes are: Euphorbiinae, Neoguillauminiinae and Anthosteminae. The 5 genus general are: Argythamnia, Caperonia, Chiropetalum ...

, subtribe Euphorbiinae (''

Euphorbia ''Euphorbia'' is a large and diverse genus of flowering plants, commonly called spurge, in the family (biology), family Euphorbiaceae. Euphorbias range from tiny annual plants to large and long-lived trees, with perhaps the tallest being ''Eu ...

'' and close relatives) show a highly specialized form of

pseudanthium A pseudanthium (; : pseudanthia) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, composite flowers ...

("false flower" made up of several true flowers) called a

cyathium A cyathium (: cyathia) is one of the specialised Pseudanthium, pseudanthia ("false flowers") forming the inflorescence of plants in the genus ''Euphorbia'' (Euphorbiaceae). A cyathium consists of: * Five (rarely four) bracteoles. These are sm ...

. This is usually a small, cup-like

involucre In botany, a bract is a modified or specialized leaf, associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves in size, color, shape or texture. They also look ...

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 (; ; : gynoecia) 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 (botany), whorl of a flower; it consists ...

with branched stigmas. This whole arrangement resembles a single flower. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

is usually a

schizocarp A schizocarp is a dry fruit that, when mature, splits up into mericarps. There are different definitions: * Any Dry fruits, dry fruit composed of multiple carpels that separate. : Under this definition the mericarps can contain one or more ...

, but sometimes a

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

. 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

phytotoxin Phytotoxins are substances that are poisonous or toxic to the growth of plants. Phytotoxic substances may result from human activity, as with herbicides, or they may be produced by plants, by microorganisms, or by naturally occurring chemical react ...

s (toxic substances produced by plants), including

diterpene Diterpenes are a class of terpenes composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being a primary ...

ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...

alkaloid Alkaloids are a broad class of natural product, naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids. Alkaloids are produced by a large varie ...

s, and

cyanogenic glycoside In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. ...

s (e.g. root tubers of

cassava ''Manihot esculenta'', common name, commonly called cassava, manioc, or yuca (among numerous regional names), is a woody shrub of the spurge family, Euphorbiaceae, native to South America, from Brazil, Paraguay and parts of the Andes. Although ...

). The seeds of the

castor oil Castor oil is a vegetable oil pressed from castor beans, the seeds of the plant ''Ricinus communis''. The seeds are 40 to 60 percent oil. It is a colourless or pale yellow liquid with a distinct taste and odor. Its boiling point is and its den ...

plant ''

Ricinus communis ''Ricinus communis'', the castor bean or castor oil plant, is a species of perennial flowering plant in the spurge family, Euphorbiaceae. It is the sole species in the monotypic genus, ''Ricinus'', and subtribe, Ricininae. The evolution of ca ...

'' contain the highly

toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subst ...

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 Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latices are found in nature, but synthetic latices are common as well. In nature, latex is found as a wikt:milky, milky fluid, which is present in 10% of all floweri ...

is a characteristic of the subfamilies

Euphorbioideae The Euphorbioideae are a subfamily within the family Euphorbiaceae 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 Euphorbia, the typ ...

and

Crotonoideae The Crotonoideae (crotonoids) is a subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end ...

, and the latex of the rubber tree ''

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

poison A poison is any chemical substance that is harmful or lethal to living organisms. 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 figurati ...

ous in the Euphorbioideae, but innocuous in the Crotonoideae. White mangrove, also known as blind-your-eye mangrove latex (''

Excoecaria agallocha ''Excoecaria agallocha'', a mangrove species, belongs to the genus ''Excoecaria'' of the family (biology), family Euphorbiaceae. The species has many common names, including blind-your-eye mangrove, blinding tree, buta buta tree, milky mangrove ...

''), causes blistering on contact and temporary blindness if it contacts the eyes, hence its name. The latex of spurge was used as a

laxative Laxatives, purgatives, or aperients are substances that loosen stools and increase bowel movements. They are used to treat and prevent constipation. Laxatives vary as to how they work and the side effects they may have. Certain stimulant, lubri ...

. Twenty first century molecular studies have shown that the enigmatic family

Rafflesiaceae The Rafflesiaceae are a family of rare parasitic plants comprising 36 species in 3 genera found in the tropical forests of east and southeast Asia, including ''Rafflesia arnoldii'', which has the largest flowers of all plants. The plants are e ...

, which was only recently recognized to belong to order

Malpighiales The Malpighiales comprise one of the largest Order (biology), orders of flowering plants. The order is very diverse, with well-known members including willows, Viola (plant), violets, aspens and Populus, poplars, Euphorbia pulcherrima, poinsett ...

, is derived from within the Euphorbiaceae. Euphorbiaceae are monoecious and open pollinated and so

self-incompatibility Self-incompatibility (SI) is a general name for several genetic mechanisms that prevent self-fertilization in sexually reproducing organisms, and thus encourage outcrossing and allogamy. It is contrasted with separation of sexes among individuals ...

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 ...

Chamaesyce ''Chamaesyce'' is a subgenus (formerly considered a genus) of plants in the family Euphorbiaceae. Recent phylogenetic studies have shown that ''Chamaesyce'' is deeply nested within the broader ''Euphorbia''. Specifically, ''Chamaesyce'' is very ...

'' 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 ...

'' 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 an ...

'' 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 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 Euphorbia, the type ...

'', ''

'' 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 and early Paleogene geologic unit in India. These beds are found as interbeds between Deccan Traps layers, including the slightly older Lameta Formation. They consist a number of different subgroups ...

of India, dating to the late

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

at the end of the Cretaceous, around 66 million years ago.

Uses and toxicity

Some species of Euphorbiaceae have economic significance, such as

(''Manihot esculenta''), castor oil plant (''

Ricinus ''Ricinus communis'', the castor bean or castor oil plant, is a species of perennial flowering plant in the spurge family, Euphorbiaceae. It is the sole species in the monotypic genus, ''Ricinus'', and subtribe, Ricininae. The evolution of c ...

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: Mexico, the Caribbean and Central and South America. It is originally native to the tropical areas of the Americas ...

''), and the Pará rubber tree (''Hevea brasiliensis''). Many are grown as

ornamental plant Ornamental plants or ''garden plants'' are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars th ...

s, such as poinsettia (''

Euphorbia pulcherrima The poinsettia (; ''Euphorbia pulcherrima'') is a commercially important flowering plant species of the diverse spurge family Euphorbiaceae. Indigenous to Mexico and Central America, the poinsettia was first described by Europeans in 1834. It ...

'') or garden croton (''Codiaeum variegatum''). Leafy spurge ('' Euphorbia esula'') and Chinese tallow (''Triadica sebifera'') are invasive 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 Traditional medicine (also known as indigenous medicine or folk medicine) refers to the knowledge, skills, and practices rooted in the cultural beliefs of various societies, especially Indigenous groups, used for maintaining health and treatin ...

, , 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'', 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 The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...

mainly because of the toxic sap.

Phytochemistry

Phytochemicals Phytochemicals are naturally-occurring chemicals present in or extract, extracted from plants. Some phytochemicals are nutrients for the plant, while others are metabolites produced to enhance plant survivability and reproduction. The field ...

found in Euphorbiaceae species include

diterpenoid Diterpenes are a class of terpenes composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being a primar ...

terpenoid The terpenoids, also known as isoprenoids, are a class of naturally occurring organic compound, organic chemicals derived from the 5-carbon compound isoprene and its derivatives called terpenes, diterpenes, etc. While sometimes used interchangeabl ...

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,

tannin Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and Precipitation (chemistry), precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' is widel ...

s, neriifolins (also found in

oleander ''Nerium oleander'' ( ), commonly known as oleander or rosebay, is a shrub or small tree cultivated worldwide in temperate and subtropical areas as an ornamental and landscaping plant. It is the only species currently classified in the genus ...

cycloartenol Cycloartenol is an important triterpenoid often found in plants. It belongs to the sterol class of steroids. It is the starting point for the synthesis of almost all plant steroids, making them chemically distinct from the steroids of fungi and a ...

, lectin, and

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

, 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