Theleaves are alternate, seldom opposite, withstipules. They are mainly simple, but where compound, are alwayspalmate, neverpinnate. Stipules may be reduced tohairs, glands, orspines, or in succulent species are sometimes absent.
The plants can bemonoecious ordioecious. The radially symmetricalflowers 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. Thestamens (the male organs) number from one to 10 (or even more). The female flowers arehypogynous, that is, with superiorovaries.
The genera in tribeEuphorbieae, subtribe Euphorbiinae (Euphorbia and close relatives) show a highly specialized form ofpseudanthium ("false flower" made up of several true flowers) called acyathium. This is usually a small, cup-likeinvolucre 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 singlepistil with branchedstigmas. This whole arrangement resembles a single flower.
Thefruit is usually aschizocarp, but sometimes adrupe. 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.
A milkylatex is a characteristic of the subfamiliesEuphorbioideae andCrotonoideae, and the latex of the rubber treeHevea brasiliensis is the primary source of natural rubber. The latex ispoisonous in the Euphorbioideae, but innocuous in the Crotonoideae.[citation needed] 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 alaxative.
Twenty first century molecular studies have shown that the enigmatic familyRafflesiaceae, which was only recently recognized to belong to orderMalpighiales, is derived from within the Euphorbiaceae.[6]
Euphorbiaceae are monoecious andopen pollinated and soself-incompatibility is rare - although it has been reported in the past, apparently this was in error. It is confirmed to be absent or incomplete inherbaceousChamaesyce by Ehrenfeld 1976,Hevea by Bouharmont 1962, andManihot by Jennings 1963 and George & Shifriss 1967.[7]
There is evidence that euphol, a tetracyclic triterpene alcohol, and the main constituent of the sap of the medicinal plantEuphorbia tirucalli, has anti-cancer activity.[14] 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.[15]
Numerous Euphorbiaceae species are listed on the poisonous plant database of the USFood and Drug Administration mainly because of the toxic sap.[16]
Some species of this family are facing the risk of extinction.[18][19] These include theEuphorbia speciesE. appariciana,E. attastoma,E. crossadenia,[20] andE. gymnoclada.
^Gucker, Corey L (2010)."Euphorbia esula". Fire Effects Information System, U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Archived fromthe original on 20 May 2022. Retrieved10 June 2019.
^Olson, Mark E.; Lomelí S., José A.; Cacho, N. Ivalú (2005). "Extinction threat in the Pedilanthus clade (Euphorbia, Euphorbiaceae), with special reference to the recently rediscovered E. conzattii (P. pulchellus)".American Journal of Botany.92 (4):634–641.doi:10.3732/ajb.92.4.634.ISSN0002-9122.PMID21652441.
