Spiraea formosana Hayata var. brevistyla Hayata; S. japonica Linnaeus f. var. formosana (Hayata) Masamune subvar. brevistyla (Hayata) Masamune.

Shrubs to 1.5 m tall. Branches reddish brown, slender; young branchlets terete, puberulous. Petiole 1–2 mm, winged, pubescent; leaf blade paler abaxially, green adaxially, ovate-oblong, 2–3.5 × 1–1.8 cm, papery, glabrous on both surfaces, midvein and 4 or 5 pairs of lateral veins raised abaxially, slightly depressed adaxially, base cuneate, margin sharply doubly serrate, apex acute to acuminate. Corymbs terminal, compound, to 5 × 5.5 cm; rachis and pedicels finely pubescent; pedicels slender, 3–4 mm, to 6–8 mm in fruit; bracts subulate, ca. 1 mm. Flowers 4–5 mm in diam. Hypanthium rotate-campanulate, pubescent abaxially. Sepals triangular, 0.5–1 mm, apex subacute. Petals obovate, 2–3 mm, apex obtuse or subemarginate. Stamens ca. 20, long exserted; filaments 4–5 mm. Follicles erect, 2–3 mm, glabrous, slightly rostrate.

Montane regions; 3000--3500 m. C Taiwan.