A tree 50 to 70 ft high; young shoots slightly hairy, and with a few scattered, whitish lenticels; buds ovate, slender-pointed, of a pale shining green, not viscid. Leaves ovate-oblong, mostly heart-shaped, often unequal at the base, slenderly pointed, irregularly toothed, the teeth finely pointed and often incurved; 2 to 4 in. long, half as wide; dull green with flattened, silky hairs all over the upper surface, but confined to the veins and midrib beneath; the lower surface is also dotted with glands; veins in about twelve pairs; stalk 1⁄3 to 1⁄2 in. long, hairy. Fruiting catkins egg-shaped, 3⁄4 in. long, 1⁄2 in. wide; scales downy, the middle lobe blunt, and about twice as long as the side ones.
Native of Japan; introduced to Kew in 1896. It was long grown under the name B. ulmifolia, but this species and B. grossa are now considered to be one and the same. Except for a certain liability to injury by late spring frost, it is apparently hardy, and is distinct in its leaf-buds and heart-shaped, many-ribbed leaves. The bark and twigs are aromatic, as in the allied American species B. lenta and lutea. A tree at Kew, pl. 1936, measures 39 × 21⁄2 ft (1967). There is a group at Albury Park, Surrey, of which the largest is 45 × 31⁄4 ft.