Euphorbia humifusa Willd.

There is no clear way of separating Euphorbia humifusa from E. inaequalis, which is widely distributed in Africa and expands the distribution and synonymy considerably.

This species is used medicinally.

Herbs, annual, 20(-30) cm tall. Root fibrous, 2-3 mm, usually single. Stems many from base, prostrate or ascending, 1-3 mm thick, often red or pinkish red, glabrous or pilose. Leaves opposite; stipules membranous, deeply divided into often threadlike lobes, to 1.5 mm, caducous; petiole 1-2 mm; leaf blade oblong or elliptic, 5-10 × 3-6 mm, adaxially green, abaxially light green, sometimes light red, both surfaces glabrous or pilose, base obliquely truncate, margin finely serrulate above middle, apex obtuse. Cyathia single, axillary, peduncle 1-3 mm; involucre turbinate, ca. 1 × 1 mm, marginal lobes 4, triangular; glands 4, oblong, appendages white or pink-red. Male flowers many, as high as cup. Female flower: ovary 3-angular-ovoid, smooth and glabrous; styles free, persistent; stigma 2-lobed. Capsule 3-angular-ovoid-globose, ca. 2 × 2.2 mm, smooth. Seeds 3-angular-ovoid-globose, ca. 1.3 × 0.9 mm, gray, each side smooth; caruncle absent. Fl. and fr. May-Oct. 2n = 22*.

Throughout China except Hainan [widely distributed in temperate regions of Africa, Asia, and Europe].

Fields, roadsides, sandy hills, seashores, slopes, very common, usually in open situations; near sea level to 3000(-3800) m.

Chamaesyce humifusa (Willdenow) Pro khanov; Euphorbia granulata Forsskål var. dentata N. E. Brown; E. inaequalis N. E. Brown; E. parvifolia E. Meyer ex Boissier; E. pseudochamaesyce Fischer; E. sanguinea Klotzsch & Garcke; E. tashiroi Hayata.