太白花楸 tai bai hua qiu

Sorbus giraldiana C. K. Schneider; S. tianschanica Ruprecht var. tomentosa C. Y. Yang & Y. L. Han.

Shrubs or small trees, ca. 4 m tall. Branchlets brownish or grayish brown, terete, with distinct lenticels, white pubescent when young, glabrous when old; buds narrowly ovoid, 0.9–1.7 cm, apex acuminate; scales several, brownish, white pubescent. Leaves imparipinnate, together with rachis 9–18 cm; petiole 1.5–2.7 cm; stipules caducous, linear-lanceolate, 5–7 mm, membranous, margin entire; rachis sulcate, slightly winged, white pubescent; leaflets (4 or)5- or 6(or 7)-paired, at intervals of 1–2 cm, blade dark green adaxially, ovate-lanceolate or elliptic-lanceolate, 4–6.5 × 1–1.7 cm, terminal and basal ones slightly smaller than middle ones, abaxially with white hairs along midvein, adaxially glabrous, base obliquely rounded, margin sharply serrate, subentire basally or lower 1/3, apex shortly acuminate. Inflorescences 5–9 × 5–8 cm, loosely many flowered; rachis and pedicels white pubescent; bracts linear, 4–6 mm, membranous, margin entire. Pedicel 5–8 mm. Flowers 1.5–2 cm in diam. Hypanthium campanulate, abaxially glabrous. Sepals triangular, 1.5–2.5 mm, abaxially glabrous or sparsely white pubescent only along margin, apex obtuse. Petals white, broadly ovate or suborbicular, 5–8 × 5–7 mm, adaxially with white hairs near base, apex obtuse. Stamens ca. 20, ca. 1/2 as long as petals or shorter. Styles usually 5, not exceeding stamens, densely white tomentose basally. Fruit red, globose, 8–10 mm in diam.; sepals persistent. Fl. Jun, fr. Sep.

Coniferous forests, thickets on mountain slopes, mountain summits; 1900--3500 m. Gansu, Qinghai, Shaanxi, Xinjiang.