43. Spiraea laeta Rehder in Sargent, Pl. Wilson. 1: 442. 1913.
华西绣线菊 hua xi xiu xian ju
Shrubs to 1.5 m tall. Branchlets often erect, sometimes tortuous, brownish to red-brown, slightly angled when young, mostly glabrous; buds oblong, 2–4 mm, with several scales, glabrous, apex acute or shortly acuminate. Petiole 4–6 mm, glabrous or pilose; leaf blade ovate, broadly so, or elliptic-ovate, 1–5.5 × 0.7–3.5 cm, glabrous on both surfaces, sometimes with tufted hairs in vein axils abaxially, or sparsely sericeous-pubescent abaxially, base cuneate to subrounded, margin irregularly serrate from base or above middle (on sterile branchlets incised doubly serrate), or sparsely shallowly incised crenate, apex acute. Racemes umbellate, 3–4 × 2–3 cm, 5–15-flowered; pedicels 8–17 mm, glabrous; bracts linear, 1.5–3 mm, glabrous. Flowers 8–12 mm in diam. Hypanthium campanulate, glabrous abaxially. Sepals broadly triangular, 2–3 × 1.5–2.5 mm, usually reflexed in fruit, apex acute. Petals white, broadly ovate or suborbicular, 2.5–5 × 2–4.5 mm, glabrous, base shortly clawed, apex obtuse. Stamens 30–40, slightly longer than petals. Disk annular, shallowly crenate. Styles shorter than stamens. Follicles slightly spreading, glabrous or slightly pubescent adaxially; styles terminal, divergent or suberect. Fl. Apr–Jun, fr. Jul–Oct.
Mixed forests on slopes, thickets, stream sides, open places, roadsides; below 3200 m. Gansu, Guizhou, Henan, Hubei, Sichuan, Yunnan.