Herbs perennial, stoloniferous, glabrous, dioecious. Tubers brownish, conic, from thickened nodes. Stems simple, thin, 6-20 cm tall, 1-2 mm in diam., somewhat succulent; internodes long inferior, very short superior. Leaves crowded on upper 2 or 3 nodes, opposite, sometimes 4 in whorl; stipules persistent, deltoid, ca. 1 mm, membranous; petiole slender, unequal in length, 1-5 mm; leaf blade linear or oblong-lanceolate, slightly asymmetric, unequal in size, 3-9 × 0.5-1 cm, membranous, lateral veins 6-10 each side, base attenuate, obtusely rounded or emarginate, cystoliths linear, margin sharply serrate, apex long acuminate or attenuate. Inflorescences in upper nodes, compact captitula; peduncle 1-2 cm; glomerules few flowered. Male flowers pedicellate, ca. 1.5 mm; perianth lobes obovate, connate 1/2 of length, subapically corniculate; rudimentary ovary minute, conic. Female perianth lobes unequal, abaxial lobe cymbiform, longer, lateral 2 lobes triangular-ovate, much shorter. Achene ovoid, 1-1.2 mm, compressed, oblique, smooth, enclosed by persistent perianth. Fl. Jun-Jul, fr. Aug-Sep.

Shaded moist places in forests, mossy rocks, near streams; 2900-3100 m. S Xizang [Bhutan, N India, Nepal, Sikkim].