Rubus pectinellus var. trilobus Koidzumi.

Herbs or subshrubs, 8–20(–30) cm tall. Stems creeping, brown or brownish, rooting at nodes, villous, ± prickly. Leaves simple; petiole 3–6 cm, villous, with needle-like prickles; stipules free, 6–9 mm, villous, deeply digitately lobed; lobes linear-lanceolate; blade suborbicular, 2.5–4.5 × 3–5(–7) cm, venation pedate, lateral veins (1 or) 2 pairs, raised abaxially, both surfaces pilose, abaxially with needle-like prickles along veins, base deeply cordate, margin sometimes undulate-lobed or 3-lobed, unevenly dentate or doubly serrate, apex obtuse. Inflorescences 1-flowered, rarely flowers 2 or 3 in axils of apical leaves; bracts 5–8 mm, villous, palmately lobed; lobes linear-lanceolate. Pedicel 2–4 cm, villous, with needle-like prickles. Flowers to 2 cm in diam. Calyx 1.5–2 cm, abaxially villous and with needle-like prickles; tube ovoid-globose; sepals ovate to ovate-lanceolate, unequal in length, outer sepals broader, 0.9–1.3 cm × 6–9 mm, deeply divided or incised, inner sepals narrower, with few teeth or entire. Petals white, obovate or elliptic, 0.8–1.2 cm × 6–8 mm, glabrous, base clawed. Stamens many, much shorter than petals. Pistils shorter than stamens; apex of ovary and base of style slightly puberulous, glabrescent. Aggregate fruit red, globose, 1–1.5 cm in diam., glabrous, with reflexed sepals; pyrenes nearly smooth or somewhat rugulose. Fl. May–Jun, fr. Jul–Aug. 2n = 42.

Montane forests and valleys, river banks; 700--3000 m. Fujian, Guizhou, Hubei, Hunan, Jiangxi, Sichuan, Taiwan, Yunnan, Zhejiang [Japan, Philippines].