Erect to sprawling, 1-3m tall. Stems thick, crooked, almost unbranched but often entangled, armed with numerous large yellow spines up to 1cm long; wood has a sweetish odour. Leaves are alternate, deciduous and large (up to 35cm across), maple-leaf shaped, with 7-9 sharply pointed and heavily toothed lobes, numerous spines on underside. Flowers are small and whitish, numerous in compact heads arranged in pyramidal terminal clusters. Fruits are bright red, flattened, shiny berries in large, showy, pyramidal clusters. Not edible by humans (bears relish them).
Moist woods, especially in wet but well-drained seepage sites and along streams, also in avalanche tracks; low to middle elevations (sometimes in subalpine forest, and to timberline in the north).