18. Berchemia flavescens (Wallich) Brongniart, Mém. Fam. Rhamnées. 50. 1826.
黄背勾儿茶 huang bei gou er cha
Ziziphus flavescens Wallich in Roxburgh, Fl. Ind. 2: 367. 1824; Berchemia hypochrysa C. K. Schneider.
Shrubs scandent, 7-8 m tall, glabrous. Branchlets spreading, yellow or turning brown. Stipules caducous; petiole 1.3-2.5 cm, glabrous; leaf blade adaxially green, turning yellow when dry, ovate, ovate-elliptic, or oblong, 7-15 × 3-7 cm, papery or subleathery, adaxially glabrous, lateral veins 12-18 pairs, prominent on both surfaces, base rounded, apex obtuse to acute, mucronulate. Flowers yellow-green, very small, ca. 1.5 mm, glabrous, usually 1 to few in fascicles, in narrow cymose panicles, rarely cymose racemes at ends of lateral branches. Pedicel 2-3 mm. Calyx tube shallowly dish-shaped; lobes narrowly triangular. Petals obovate, distinctly hooded. Stamens nearly completely enfolded by petals. Disk thick, fleshy. Ovary deeply immersed in disk; style cylindric, short, stout; stigma 2- or 3-lobed. Drupe purple-red or purple-black at maturity, subcylindric, 7-11 mm, 4-5 mm in diam., base with persistent cup-shaped disk, apex mucronulate; mesocarp thin, sour-sweet-tasting; fruiting pedicel 3-5 mm, glabrous. Fl. Jun-Aug, fr. May-Jul of following year.
Forests and thickets on slopes; 1200-4000 m. E Gansu, W Hubei, S Shaanxi, Sichuan, S and SE Xizang, NW Yunnan [Bhutan, India, Nepal].