乳浆大戟亚属 ru jiang da ji ya shu

Esula (Persoon) Haworth (1812), not Morandi (1761); Tithymalus Gaertner (1790), nom. cons., not Miller (1754).

Herbs and shrubs, annual to perennial. Stems often little branched, often hollow, often dying after flowering. Leaves usually alternate; stipules absent; leaf blade symmetrical, usually persistent. Inflorescence usually a terminal pseudumbel, sometimes compound, sometimes also with axillary cymes from uppermost axils forming cylindric thyrse. Cyathia subtended by cyathophylls longer than cyathia, mostly green, occasionally colored; glands usually 4, sometimes 5, simple or with 2 horns. Capsules often exserted, sometimes papillate. Seeds with or without caruncle.

About 500 species: most numerous in temperate Asia and Europe, extending into montane regions of the tropics; 46 species (seven endemic) in China.

Most members are very easily recognized by the monocarpic stems, lack of stipules, and pseudumbellate inflorescences.