36. Euphorbia tibetica Boissier in A. Candolle, Prodr. 15(2): 114. 1862.
西藏大戟 xi zang da ji
Herbs, perennial, usually erect or ascending, 10-15(-30) cm tall. Rootstock vertical, cylindric, up to more than 10 cm, to 10 mm thick but often less, many branched at apex. Stems densely clustered, mostly sterile, 1-2(-5) mm thick, glabrous. Leaves alternate; stipules absent; basal scale-leaves few; petiole absent or nearly so; leaf blade obovate to oblong-lanceolate, 6-15 × 3-6 mm, base attenuate, margin entire, repand, or dentate, apex rounded; lateral veins inconspicuous. Inflorescence an ill-defined terminal pseudumbel or dichasial cyme; involucral leaves 2 or 3, ovate-triangular, sometimes oblique, margin denticulate, base attenuate, primary rays 2 or 3, 0.2-2.5 cm; cymes ca. 3 × forked; cyathophylls 2, similar to primary involucral leaves. Cyathium stipitate; involucre turbinate, 3.5-4.5 × 3-5 mm, lobes entire, bent inside; glands 5, dark brown, rounded to transversely oblong, entire. Male flowers many, slightly exserted from involucre. Female flower: ovary pedicellate and extended out of cup, smooth, glabrous; styles very short, free, persistent; style arms slightly 2-lobed. Capsule shortly terete, ca. 5 × 5 mm, smooth, glabrous. Seeds ovoid-globose, 3-4 × 1.7-3 mm, brown to black-brown, smooth without modification; caruncle trigonous, yellow. Fl. and fr. Jun-Sep.
Deserts, semidesert areas, dry and semidry fields; 2500-5000 m. Xinjiang, Xizang [NW India, Kazakhstan, Kyrgyzstan, N Pakistan, Tajikistan].