细尾楼梯草 xi wei lou ti cao

Subshrubs, monoecious or rarely dioecious, 20-100 cm tall. Stems ascending or erect, branched, glabrous or pubescent. Leaves alternate; nanophylls absent; stipules subulate, 2-5 × 0.1-0.3 mm, glabrous, without cystoliths; petiole 0-1 mm; leaf blade obliquely oblanceolate-oblong or oblong, 3-9.5 × 1-2.5 cm, herbaceous, major basal lateral veins both arising at base of leaf blade, sometimes not extending beyond middle of leaf, both surfaces glabrous, or only abaxial surface pubescent; cystoliths conspicuous, dense, very small; base with broader half obtuse or nearly rounded, margin dentate, apex cuspidate or caudate-cuspidate. Male inflorescences solitary, simple, 3-5 mm in diam., sessile or subsessile; receptacle nearly absent; bracts broadly lanceolate, 1.2-1.5 mm; bracteoles lanceolate-linear. Female inflorescences solitary, 1-4 mm in diam., sessile; receptacle very small; bracts ovate to triangular; bracteoles lanceolate-linear. Male flowers 4-merous. Achenes ellipsoid, 6-ribbed. Fl. Mar-Apr.

Evergreen broad-leaved forests in valleys, dark damp places in forests, valley streamsides; 300-2200 m. NW Guangxi, S Guizhou, S Yunnan [N Vietnam].