A deciduous climber up to 40 ft or more high, attaching itself to tree trunks by aerial roots in the wild; young shoots either hairy or glabrous; the bark of the older branches peeling off in large, thin, brown flakes. Leaves ovate or oval, 3 to 5 in. long (more in mild climates), half to three-fourths as wide, rounded at the base, pointed, regularly triangular- or roundish-toothed, glabrous on both sides except for tufts of down in the vein-axils beneath; stalk at first hairy, 1 to 3 in. long. Corymbs 6 to 8 in. across, with a few white sterile flowers at the margins, each 2⁄3 to 11⁄2 in. in diameter; the small fertile flowers are yellowish white; stamens nine to fifteen. Blossoms in June.
Native of the Himalaya and China; introduced in 1839. It is nearly allied to H. petiolaris, but differs in having fewer stamens, not so flat an inflorescence, and usually more coarsely toothed leaves. It is not so hardy probably as H. petiolaris, although it grows well outside on a wall at Kew. Both these species are distinguished by the petals of the fertile flowers cohering into, and falling away in, one cap-like piece.