38. Spiraea trilobata Linnaeus, Mant. Pl. 2: 244. 1771.
三裂绣线菊 san lie xiu xian ju
Shrubs 1–2 m tall. Branchlets spreading, tortuous, yellow-brown or purple-brown, turning dark gray-brown, slender, glabrous; buds broadly ovoid, small, with several scales, glabrous, apex obtuse. Petiole 3–5 mm, glabrous; leaf blade suborbicular, 1.7–3 × 1.5–3 cm, glabrous or abaxially sparsely pubescent, conspicuously 3–5-veined, base subcordate or rounded, rarely cuneate, margin slightly crenate above middle, usually 3-lobed, apex obtuse. Umbels pedunculate, 2–4(–5) cm, 15–30-flowered; pedicels 8–13 mm, glabrous or sparsely pubescent; bracts oblanceolate or linear, 4–7 mm, deeply divided into slender lobes. Flowers 6–8 mm in diam. Hypanthium campanulate, glabrous or sparsely pubescent abaxially. Sepals triangular, 1.5–2 mm, erect in fruit, apex acute. Petals white, broadly obovate, 2.5–4 mm in diam., apex emarginate. Stamens 18–20, shorter than petals. Disk annular, 10-lobed; lobes unequal, apex emarginate. Carpels pubescent; styles shorter than stamens. Follicles spreading, glabrous or puberulous only on adaxial suture; styles slightly divergent. Fl. May–Jun, fr. Jul–Aug.
Thickets, open rocky slopes, montane regions; 400--2400 m. Anhui, Gansu, Hebei, Heilongjiang, Henan, Jiangsu, Liaoning, Nei Mongol, Shaanxi, Shandong, Shanxi, Xinjiang [Korea, Russia].
