纤细花楸 qian xi hua qiu

Sorbus poteriifolia Handel-Mazzetti, p.p.

Shrubs 1.5–4.5 m tall. Branchlets brown or reddish brown when young, grayish black when old, reddish brown pubescent when young, prominently lenticellate when old; buds ovoid, 3–6 mm, apex ± obtuse or acute; scales several, dark brown, brown pubescent. Leaves imparipinnate, together with rachis 5–10 cm; petiole 0.5–1.5 cm; stipules caducous, purple, minute, 2–3 mm; rachis abaxially sparsely brown pubescent, narrowly winged, adaxially shallowly sulcate; leaflet blades usually 8–13 pairs, at intervals of 3–6 mm, elliptic or ovate-elliptic, 0.6–1.4 cm × 4–8 mm, lateral veins 4 or 5 pairs, both surfaces glabrous, base broadly cuneate or rotund, margin 3–5- coarsely toothed per side, apex obtuse or ± acute. Inflorescences corymbose or compound-corymbose, 3–6 cm, 3–10(–12)-flowered; rachis and pedicels glabrous or sparsely brown pubescent, glabrous in fruit; bracts caducous, linear, 1–3 mm, glabrous. Pedicel 7–10 mm. Hypanthium purple, campanulate, abaxially glabrous. Sepals triangular, 1.5–2.5 mm, apex obtuse. Petals crimson, broadly ovate, 4–5 × 3–4 mm, glabrous, apex obtuse. Stamens 20, shorter than petals. Styles 3–5, ca. as long as stamens, puberulous basally. Fruit dark red, ovoid-globose, 7–8 mm in diam., somewhat glaucous; sepals persistent. Fl. May–Jun, fr. Aug–Sep. 2n = 68*.

Thickets of high mountains, river banks, stony slopes; 3000--4000 m. Xizang, NW Yunnan [N Myanmar].

For an apomictic microspecies, this taxon is remarkably constant over a wide geographic range.