Ohwi 1985 Flora of Japan

the young branches rusty-brown soft pubescent; leaves large, rather thin, cordate, 5-angled, depressed, 10-15 cm. long, 12-20 cm. wide, glabrous or nearly so on upper side, often tliinly rusty brown curled-pubescent, persistently so on the nerves beneath, shallowly 5-lobed, the lobes broadly deltoid, often shallowly 3-fid, sharply double-serrate, acuminate, the petioles 8- 17 cm. long, with persistent sparse brown pubescence on upper part; inflorescence erect, rather densely many-flowcred, 10-20 cm. long, on a short peduncle 1，1.5 cm. long, short- branched in lower part, densely rusty-brown pubescent, the pedicels spreading, 4-7 mm. long; flowers 3-4 mm. across; sepals ovate, 1 mm. long; petals small; stamens 3 mm. long; samaras ascending to obliquely spreading, rusty brown pubescent, 3.5-4 cm. long.

June-July.

Mountains; Honshu, Shikoku, Kyushu; rare.