Elatostema microcephalanthum Hayata

Herbs perennial, monoecious, 10-20 cm tall. Stems ascending, branched, glabrous. Leaves alternate; nanophylls absent; stipules lanceolate or linear, 0.6-2 × 0.2-0.6 mm, glabrous; petiole 0-1 mm; leaf blade obliquely rhombic-elliptic or nearly rhombic, 1-6 × 0.8-2 cm, herbaceous or membranous, major basal lateral veins both arising at base of leaf blade, abaxial surface strigillose along veins, adaxial surface glabrous, cystoliths obscure or conspicuous, sparse, only present along margins; base with broader half rounded, margin obtusely serrate, apex obtusely acute to acutely acuminate. Male inflorescences solitary, simple, 4-8 mm in diam., peduncle to 4 cm; receptacle obscure; bracts connate, ca. 4 mm. Female inflorescences solitary, 30-flowered or more, 3-4 mm in diam.; peduncle 0-3 mm; receptacle small; bracts narrowly oblong; bracteoles spatulate or linear. Male flowers 5-merous. Achenes ovoid, 5- or 6-ribbed. Fl. Jun-Jan.

Wet floors in ravines at medium elevations. Taiwan [S Japan].