57. Spiraea mongolica Maximowicz, Bull. Acad. Imp. Sci. St.-Pétersbourg. 27: 467. 1881.
蒙古绣线菊 meng gu xiu xian ju
Shrubs to 3 m tall. Branchlets red-brown to gray-brown, slender, angled, glabrous or densely shortly tomentose when young; buds long ovoid, longer than petioles, with 2 brownish scales, glabrous or densely shortly tomentose, apex long acuminate. Petiole 1–2 mm, glabrous or densely shortly tomentose; leaf blade abaxially paler, oblong or elliptic, 8–20 × 3.5–7 mm, glabrous on both surfaces, rarely puberulous abaxially, pinnately veined, base cuneate, margin entire, rarely with a few teeth near apex, apex obtuse, acute, or mucronate. Racemes pedunculate, umbellate, 2–5 × 1.5–3 cm, 8–15-flowered; rachis and pedicels glabrous; pedicels 5–10 mm; bracts linear, 1.5–3 mm, glabrous, caducous. Flowers 5–7 mm in diam. Hypanthium subcampanulate, glabrous abaxially. Sepals triangular, 1–2 × 1.5–2.5 mm, erect or slightly reflexed in fruit, apex acute. Petals white, suborbicular, 2–4 mm, about as broad as long, glabrous, base shortly clawed, apex obtuse, rarely emarginate. Stamens 18–25, nearly equaling petals. Disk annular, 10-lobed; lobes orbicular. Carpels pubescent; styles shorter than stamens. Follicles straightly spreading, glabrous, wholly pubescent, or puberulous only on adaxial suture; styles abaxial. Fl. May–Jul, fr. Jul–Sep.
Forests, thickets, sunny rocky slopes, mountain summits, rocky valleys, stream sides; 1500--4700 m. Gansu, Hebei, Henan, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shanxi, Sichuan, Xinjiang, Xizang.
