Description from Flora of China
Spiraea laevigata Linnaeus, Mant. Pl. 2: 244. 1771; Sibiraea altaiensis (Laxmann) C. K. Schneider; S. glaberrima K. S. Hao; Spiraea altaica Pallas; S. altaiensis Laxmann.
Shrubs to 1.5 m tall. Branchlets glabrous; buds ovoid, slightly pubescent. Leaves usually solitary at axils on current year’s growth, clustered on older branchlets; leaf blade linear-lanceolate, broadly lanceolate, or oblong-oblanceolate, 4–6.5 × 1–2.3 cm, glabrous on both surfaces, base attenuate, apex acute, rarely obtuse. Panicles 5–8 cm wide; peduncle glabrous; bracts ca. 3 mm, glabrous on both surfaces, apex acute to acuminate. Flowers ca. 5 mm in diam.; pedicel ca. 3 mm, glabrous. Hypanthium glabrous. Sepals triangular-ovate, ca. 1.5 mm, glabrous on both surfaces. Petals white, obovate, base attenuate with a broad, cuneate claw, apex rounded. Carpels glabrous. Follicles rarely spreading, 3–4 mm; fruiting pedicel 3–5 mm, glabrous. Fl. Jul, fr. Aug–Sep.
The Asian and European populations are widely disjunct, separated by over 5000 km.
Open forests, slopes, meadows, stream sides. S Gansu (Min Xian, Xigu), E Qinghai (Haiyan Xian, Xining Shi), E Xizang (Sog Xian) [Kazakhstan, Russia (Siberia); SE Europe (Bosnia, Croatia)].