Japan Flora: Tree or shrub with nearly glabrous branches; leaves ovate or broadly so, 8-20 cm. long, 5-15 cm. wide, rounded to shallowly cordate at base, larger in vigorous shoots, with short rather regular teeth, sometimes 3-4 lobed, glabrescent on both sides or puberulous beneath on nerves, slightly scabrous above, the petioles 2-6 cm. long, nearly glabrous; staminate spikes short-cylindric; fruiting spikes ellipsoidal；Apr.-May. Mountains;

Hokkaido, Honshu, Shikoku, Kyushu. Korea, Sakhalin, and s. Kuriles. China, Formosa, and Ryukyus. Much used in feeding silk worms.

Korea Flora: Deciduous small tree. Height 7-8m. Diameter 1m. Bark grayish-brown. Winter buds and branchlets: Buds broadly ovate, conical, pointed tip, 5-6 bud scales, terminal buds larger than lateral buds (3-6mm long). Branchlets with or without fine hairs, gradually turning dark brown. Leaf scars crescent-shaped or triangular. Leaves ovate or broadly ovate, margins with irregular teeth, underside with some hair on midrib. Size (2)8-15cm × (4)6-8(14)cm, apex with long tail-like tip. Stipules fall off early. Petiole (0.5)1.5-2.5(3)cm long, with fine hairs. Flowers dioecious or polygamous. Male inflorescence hanging down from base of new branches, male flowers with 4 petals and 4 stamens each. Female inflorescence elliptical, 5-15mm long, flower stalk with fine hairs. Female flowers green, petals about 2mm long, style split into 2 (2-3cm long). Fruit cluster (5)7-13(15)mm long, dark purple.

Sporophyte chromosome number: 28, 42.

Flowering Early to late May.

Fruiting Late June to mid-July.

Distribution: Central and southern China, Japan from Hokkaido to Okinawa; throughout the Korean Peninsula.

Ecological characteristics: Light-demanding, commonly grows as a shrub along hiking trails. Specimens collected from the west coast and northern Gangwon-do tend to have more sharply developed teeth on leaves compared to specimens from other regions.