Description from Flora of China
Berberis yunnanensis Franchet var. platyphylla Ahrendt, J. Bot. 79(Suppl.): 61. 1941.
Shrubs, deciduous, 1-1.5 m tall. Branches brownish gray, angulate, sparsely black verruculose; shoots dark purple, glabrous; spines 3-fid, weak, ca. 1 cm, adaxially sulcate. Petiole 2-5 mm, or leaf subsessile; leaf blade abaxially pale green, adaxially deep green, broadly obovate or elliptic, 2-5 × 1-1.4 cm, papery, abaxially sometimes slightly pruinose, midvein obviously raised, adaxially with flat midvein, both surfaces with conspicuous lateral and reticulate veins, base cuneate, margin entire or 2-4-spinose-serrate on each side, apex rounded, aristate. Inflorescence an umbellate raceme, 3-7-flowered, 3-5 cm, including peduncle 2-10 mm, sometimes with few fascicled flowers at base of peduncle. Pedicels 1.2-2 cm, glabrous; bractlets purplish red, lanceolate, ca. 3 mm. Sepals in 2 whorls; outer sepals ovate, ca. 6 × 3 mm; inner sepals oblong-obovate, 6-7 × 3.5-4 mm. Petals obovate, ca. 6 × 3 mm, base clawed, with separate glands, apex emarginate. Stamens ca. 5 mm; anther connective obviously prolonged, apiculate. Ovules 3-5. Berry oblong, ca. 10 × 7 mm, not pruinose, style not persistent. Fl. Jun, fr. Aug-Oct.
● Thickets, forests, forest margins; 3100-3500 m. Sichuan, Xizang, Yunnan.