Description from Flora of China
Trees 3–7(–10) m tall. Branchlets blackish gray, stout, with few indistinct lenticels, glabrous; buds oblong-ovoid, 6–9 mm, apex acute; scales dark brown, glabrous. Leaves imparipinnate, together with rachis 13–20 cm; petiole 2.5–4(–5) cm; stipules persistent, 5–7 mm, membranous, margin entire or slightly incised at apex, somewhat pubescent; rachis sulcate, narrowly winged, abaxially glabrous or reddish brown villous; leaflets 3 or 4 pairs, at intervals of 1.5–2.5 cm, blade pale abaxially, dark green adaxially, oblong or oblong-elliptic, (4.5–)5–9(–11) × 2–3 cm, basal pair smaller than middle ones, lateral veins 15–20 pairs, curved-anastomosing at margin, abaxially reddish brown villous along veins, adaxially glabrous or subglabrous, base broadly cuneate, rounded, or subcordate, margin serrate or doubly serrate, apex acute or obtuse. Inflorescences 7–11 × 8–15 cm, densely flowered; rachis and pedicels reddish brown villous; bracts 3–5 mm, membranous, margin entire or slightly serrate. Pedicel 2–5 mm. Flowers 6–8 mm in diam. Hypanthium campanulate, abaxially glabrous. Sepals triangular-ovate, 1–2 mm, sometimes with puberulous margin, apex acute. Petals white, orbicular-ovate, 3–4 × 2.5–3.5 mm, glabrous, apex obtuse. Stamens 20, ca. 1/3 as long as petals. Styles 5, not exceeding stamens, villous basally. Fruit white, globose, 6–8 mm in diam., glabrous; sepals persistent. Fl. Jun–Jul. 2n = 34*.
Forests in mountainous regions; 2500--3000 m. W Sichuan.