Description from Flora of China
Trees, shrubs, or herbs, rarely woody or herbaceous lianas, monoecious or dioecious, indumentum of simple, branched, stellate, or gland-tipped hairs, peltate or glandular scales or stinging hairs, latex often present, clear, white, or colored; roots woody, rarely roots tuberous and stems succulent, sometimes spiny. Leaves alternate or opposite, rarely whorled; stipules usually present, often free, sometimes modified into spines or glands, deciduous or persistent; petioles long to short, sometimes with glands at apex or base; leaf blade simple, sometimes palmately lobed, rarely compound, or reduced to scales, margins entire or toothed, sometimes with distinct glands along margin and/or on surface, venation pinnate or palmate. Inflorescences axillary or terminal, flowers in cymes or fascicles, these often arranged along an elongated axis, branched or unbranched, forming a thyrse, in congested heads, or in a flowerlike cyathium with very reduced flowers enclosed within a ± cupular involucre; bracts sometimes petaloid. Flowers unisexual, within same inflorescence or in separate inflorescences, actinomorphic. Sepals (1-)3-6(-8), free or connate into calyx tube, valvate or imbricate, rarely absent (Euphorbia). Petals free, often reduced or absent. Disk present or absent. Male flowers with disk intrastaminal or extrastaminal, entire to dissected. Stamens one to very many, hypogynous; filaments free or connate; anthers 2(-4)-locular, mostly dehiscing longitudinally, rarely transversely or by pores, introrse or extrorse; rudimentary ovary sometimes present. Female flowers rarely with staminodes; ovary superior, (1-)2-5(-20)-locular; placentation axile; ovules 1 or 2 per locule, anatropous or hemitropous; styles free or connate, entire or lobed, or multifid, lobes erect, horizontal or curved; stigma capitate, linear, fimbriate, fan-shaped or pinnatilobate. Fruit typically a capsule elastically dehiscent into 2-valved cocci from a persistent columella, sometimes a berry or drupe. Seeds 1 or 2 per locule; seed coat thin to indurate, sometimes fleshy to form a sarcotesta; caruncle sometimes present; aril sometimes present; endosperm present or absent; embryo straight to curved or folded; cotyledons usually broader than radical. x = 6-14.
Trees, shrubs, or herbs, usually without latex (present in Bischofia); indumentum of simple hairs (branched in Phyllanthus reticulatus), often absent. Leaves alternate, often distichous, sometimes scalelike on main stems; petiole usually short, usually without glands (present in Aporosa); leaf blade simple, margin entire or minutely serrulate (long petioles, 3(-5)-foliolate with toothed margins in Bischofia); venation pinnate, rarely obscurely 3-veined from base. Inflorescences mostly axillary, without visible axis (present in Antidesma, Aporosa, Baccaurea, Bischofia, Richeriella). Male flowers with 2-8 stamens, anthers longitudinally dehiscent (variable in Phyllanthus); female flowers with 2 ovules per locule. Seeds without caruncle, sometimes with fleshy aril or fleshy testa.
Trees to shrubs. Leaf blade leathery, grayish when dry, base often asymmetrical. Ovules 1 per locule; stigmas dilated, peltate or reniform. Fruit a relatively large 1-seeded drupe, usually crowned by persistent flaplike stigmas. Seeds without caruncle.
Plants with or without latex; indumentum of simple, stellate, scalelike, stinging, or glandular hairs, sometimes absent. Leaves alternate or opposite; leaf blade simple or compound, sometimes deeply divided, margin entire or variously toothed, often with sessile glands near junction with petiole and/or along margins; venation pinnate or palmate. Inflorescences basically thyrsoid, very variable, often with well-defined main axis and/or distinct cymes, rarely a sessile axillary fascicle. Ovules 1 per locule of ovary. Seed sometimes carunculate, sometimes arillate.
The Euphorbiaceae as treated here include the following families that have been proposed for segregation: Androstachydaceae, Antidesmataceae, Bischofiaceae, Hymenocardiaceae, Phyllanthaceae, Pedilanthaceae, Picrodendraceae, Porantheraceae, Putranjivaceae, Ricinocarpaceae, Scepaceae, Stilaginaceae, Trewiaceae, and Uapacaceae. The Pandaceae and Buxaceae, formerly included here, are now well established as separate families.
Molecular data has shown that the traditional concept of Euphorbiaceae includes three major lineages that are relatively distantly related to each other: the Phyllanthoids (genera 1-16 in this account), the Putranjivoids (genera 17 and 18), and the Euphorbioids (genera 19-75).
Many species of Euphorbiaceae are of economic importance, probably most importantly as the main source of rubber (Hevea) but also as sources of medicine; foods, both as a staple starch source (Manihot) and fruits (e.g., Phyllanthus emblica); seed oils (Ricinus, Vernicia); and insecticides.
Li Pingt’ao. 1994. Euphorbiaceae. In: Li Pingt’ao, ed., Fl. Reipubl. Popularis Sin. 44(1): ii-viii, 1-217; Kiu Huashing, Hwang Shumei & Chang Yongtian. 1996. Euphorbiaceae (2). In: Kiu Huashing, ed., Fl. Reipubl. Popularis Sin. 44(2): ii-ix, 1-212; Ma Jinshuang & Tseng Yungchien. 1997. Euphorbiaceae (3). In: Ma Jinshuang, ed., Fl. Reipubl. Popularis Sin. 44(3): ii-vi, 1-150.
The Putranjivoid genera resemble phyllanthoids by their 2-ranked leaves, frequently rather small fasciculate flowers, and ovules 2 per locule. They can be distinguished by their leaf blades, stigmas, and fruit. Also, the leaves contain mustard oils and so frequently taste peppery when fresh, although the taste may take a little time to develop.
About 322 genera and 8910 species: widespread throughout the world, primarily in the tropics and subtropics, more poorly represented in temperate regions; 75 genera (one endemic, nine introduced) and 406 species (99 endemic, 27 introduced) in China, nearly 95% of which are found in the S and SW parts of the country.
Fifty-nine genera and over 1700 species: mostly tropical, the greatest diversity in SE Asia; 16 genera and 138 species (41 endemic, four introduced) in China.
Four genera and ca. 210 species: throughout the tropics; two genera and 13 species (three endemic) in China.
Two hundred and eighteen genera and over 5700 species: widespread throughout the world, primarily in the tropics and subtropics, more poorly represented in temperate regions; 54 genera (one endemic, nine introduced) and 255 species (55 endemic, 23 introduced) in China.
(Authors: Li Bingtao (李秉滔 Li Ping-tao), Qiu Huaxing (丘华兴 Chiu Hua-hsing, Kiu Hua-shing, Kiu Hua-xing), Ma Jinshuang (马金双), Zhu Hua (朱华); Michael G. Gilbert, Hans-Joachim Esser, Stefan Dressler, Petra Hoffmann, Lynn J. Gillespie, Maria Vorontsova, Gordon D. McPherson)