Euphorbia hyssopifolia L.

Herbs, annual, 15-20 cm tall. Root fibrous, 0.8-1 mm. Stems many from base, ascending or suberect, rarely prostrate, ca. 1 mm thick, usually glabrous, rarely with a few hairs when young. Leaves opposite; stipules interpetiolar, truncate, 0.7-0.9 mm, shallowly lacerate; petiole 1.5-2 mm; leaf blade oblong-elliptic, 0.7-3 cm × 0.3-1.2 mm, thickly papery, base slightly oblique, asymmetric, subrounded, margin sparsely crenate, apex obtuse, adaxially with a few purple spots. Cyathia axillary and terminal, single or in small cymes, peduncle to 4 mm; involucre narrowly campanulate, ca. 0.8 × 0.4-0.5 mm, glabrous, marginal lobes 5, triangular; glands 4, yellow-green, rounded to transversely elliptic, appendages white or pale pink, wider than glands, to 0.7 × 0.5 mm, margin entire to slightly undulate. Male flowers 5-15, exserted; anthers red. Female flower pedicellate, exserted from involucre; ovary smooth, glabrous; styles free; stigma slightly 2-lobed. Capsule 3-angular-ovoid, 2-2.5 × ca. 2.5 mm, smooth, glabrous; fruiting pedicel ca. 2 mm. Seeds ovoid-tetragonal, ca. 1.1 × 0.8 mm, blackish, each side with 3 or 4 transverse furrows; caruncle absent. Fl. and fr. Jan-Apr.

Disturbed areas along railways and roads. Hainan, Taiwan (Gaoxiong, Tainan, Taizhong) [New World; naturalized in the Old World].