Description from Flora of China
Rubus nagasawanus Koidzumi var. arachnoideus (Y. C. Liu & F. Y. Lu) S. S. Ying.
Subshrubs. Branchlets densely grayish appressed tomentose, with few small prickles. Leaves simple; petiole 1.5–2 cm, grayish tomentose; stipules 4–6 mm, much lacerate, grayish tomentose; blade ovate to broadly ovate, 5–7 × 4–6 cm, palmately 5-veined, veins raised abaxially, slightly impressed adaxially, abaxially densely grayish appressed tomentose, adaxially dark brownish, glabrous or slightly pubescent along veins, base broadly cordate, margin unevenly dentate, 3–5-lobed, terminal lobe 3–4 × 3–3.5 cm, lateral lobes smaller, apex obtuse or acute. Inflorescences terminal, cymose panicles, much branched, to 17 × 13 cm; rachis and pedicels grayish tomentose. Pedicel 0.8–2 cm, bracts linear or linear-lanceolate, slightly lacerate, grayish tomentose. Calyx cupular, 5–6 mm in diam., abaxially grayish tomentose; sepals triangular or triangular-ovate, 4–6 × 2–3 mm, apex acute. Petals white, broadly obovate or obovate-spatulate, 4–5 × 3–4 mm, both surfaces sparsely pubescent, base shortly clawed; torus densely villous. Stamens many; filaments free or connate at base, ca. 3 mm, glabrous. Pistils glabrous; styles 3–4 mm. Fruit not seen. Fl. Jul–Sep(–Dec).
No specimens have been seen by the present authors. Specimens under this name at HAST have been annotated by Naohiro Naruhashi as Rubus tephrodes (Ching-I Peng, pers. comm.).
Broad-leaved forests; (300--)1500--1800 m. E Taiwan.