鞘柄木 qiao bing mu

Trees, deciduous, 3–12 m tall. Bark grayish black; old branches gray-green, glabrous. Leaves with petiole light green, 4.5–8.5 cm, glabrous; leaf blade 10–15 × 8–16.5 cm, papery, sparsely pubescent with soft trichomes, veins palmate, 7–9, conspicuous abaxially, base shallowly cordate, unlobed, margin serrate, apex acute. Inflorescences 12–22 cm, slightly pubescent. Staminate flowers: calyx tube shortly cylindrical, calyx lobes shortly triangular or sometimes not obvious; petals white, narrowly elliptic, ca. 5 mm, glabrous; stamens alternate petals; filaments ca. 0.5 mm, glabrous; anthers oblong, ca. 1.5 mm; disk flat, subcircular; pedicel 2–2.5 mm, sparsely pubescent or nearly glabrous, subtended by two bracteoles; bracteoles lanceolate, 1–2.5 mm. Carpellate flowers: calyx of carpellate flowers subovate, teeth of calyx triangular, acute; floral disk inconspicuous, flat; ovary ovoid, locules 3 or 4, glabrous. Fruit ovoid, 5–6 mm, ca. 3 mm in diam., glabrous. Fl. Nov–Mar, fr. Mar–Apr. 2n = 24.

Broad-leaved forests, forest margins, open slopes; 1600–2600 m. SE Xizang, W Yunnan [Bhutan, NE India (Darjiling), Nepal, Sikkim].