海南冷水花 hai nan leng shui hua

Subshrubs glabrous, monoecious or dioecious. Stems light green when dry, 30-100 cm; stems, stipules, petioles, and both surfaces of leaf blade densely covered with cystoliths. Stipules deciduous, green, oblong, 6-8 mm, papery, longitudinally 2-ribbed; petiole subequal in length, 1-3.5 cm; leaf blade abaxially pale green, adaxially green, elliptic or oblong, subequal in size, 7-14 × 3.5-7.5 cm, thinly papery, 3-veined, lateral veins 8-10 each side, transverse, prominent abaxially, external secondary veins anastomosing by margin, base broadly cuneate, rounded, or subcordate, margin crenate-serrate from base, apex acute or acuminate. Inflorescences unisexual or sometimes of mixed sexes, in pairs; male inflorescence a racemelike cyme, few branched, 2-4.5 cm, glomerules scattered; female inflorescence a dichotomous cyme, ca. 1.5 cm. Male flowers reddish brown, pedicellate, in bud ca. 1.5 mm; perianth lobes 4, ovate, connate 1/2 of length, subapically corniculate; stamens 4; rudimentary ovary cylindric, ca. 0.3 mm. Female flowers subsessile; perianth lobes triangular-ovate, persistent perianth 1/4 as long as achene; staminodes oblong. Achene densely purplish spotted, ovoid, ca. 2 mm, compressed, smooth. Fl. Aug-Oct, fr. Nov-Jan.

Shaded wet places in forests, near streams; 200-300 m. Guangxi, Hainan [N Vietnam].