Japan Flora: Tree, the branches glabrous, the nodes sparsely rusty-brown pubescent while young; leaves ovate to orbicular, 3-fid, 4-7 cm. long, 3-6 (-8) cm. wide, rounded to shallowly cordate at base, glabrous, deep green on upper side, glaucous beneath, the lobes 3-angled or ovate-triangular, acuminate, irregularly serrate, the petioles glabrous, 3-6 cm. long; inflorescence fasciculate, few-flowered, from lateral winter-buds developing before the leaves, the pedicels elongate, glabrous, to 5 cm. long, pendulous; sepals of pistillate flowers 5, broadly lanceolate to narrowly ovate, about 3 mm. long, reddish; petals smaller; samaras glabrous, about 2 cm. long, nearly erect.  Apr.

Wet places in mountains; Honshu (w. part of Tokaido and Shinano); rare; sometimes planted.