墨脱冷水花 mo tuo leng shui hua

Herbs perennial, weak, stoloniferous, dioecious or monoecious. Stems erect, often branched underground, 5-25 cm tall, 1.5-2 mm in diam., woody at base, succulent distally; upper stems, petioles, and inflorescences with multicellular hairs. Stipules soon deciduous, brownish, oblong-lanceolate, membranous; petiole slightly unequal in length, 5-30 mm; leaf blade elliptic or ovate-elliptic, slightly unequal in size, 1.5-8 × 1-4 cm, submembranous, 3-veined, lateral veins 10-13 each side, inconspicuous, abaxial surface pubescent, adaxial surface sparsely multicellular pilose, cystoliths minute, shortly fusiform or punctate, inconspicuous only at margins, base broadly cuneate or obtuse, margin sharply dentate, apex caudate-acuminate, acumen sharply denticulate. Inflorescence glomerules several, in moniliform spikes, sometimes few branched, rarely capitate, 1-4 cm overall, peduncle 0.5-2.5 cm; bracts ovate-oblong, ca. 0.6 mm. Male flowers purplish, ovoid, ca. 1 mm; perianth lobes 4, subapically inconspicuously corniculate; stamens 4; rudimentary ovary minute. Female perianth lobes unequal, abaxial lobe somewhat hooded, 1/2 as long as achene, lateral 2 lobes triangular-ovate, shorter, membranous. Achene ovoid, ca. 1 mm, slightly compressed, slightly oblique, verrucose, enclosed by persistent perianth. Fl. Jun-Jul, fr. Aug-Sep.

Shaded moist places of forest margins, near streams; 2400-3800 m. SE Xizang [N India].

This species was formerly included in Pilea umbrosa var. obesa, which was based on three collections, which were later recognized as three different taxa. One specimen, Wallich 4589B, from Nepal, is considered to be consistent with P. medogensis by its general appearance and inflorescence morphology. Pilea medogensis is similar to P. umbrosa, but is distinct in its moniliform spike, elliptic leaf blades, and leaf apex with a sharply denticulate acumen.