Betula Nana L. and Betula Glandulosa Michx.

Betula nana. A prostrate shrub up to 1 m in height. Twigs stiff, dull dark brown, pubescent, not warty. Young twigs are covered with resin spots. Leaves orbicular or obovate-orbicular, deeply and regularly crenate all around, rounded at both ends and glabrous (or with a few glands) at maturity. Leaves dark green above and paler beneath with a petiole up to 3 mm. Subspecies exilis (Suk.) Hult. has shorter leaf blades (0.5-1 cm long) than ssp. nana (0.5-2.0 cm). Bracts lack a resiniferous hump on the back, and possess a cuneate base and three parallel (almost equal) narrow lobes at the apex. Male inflorescence is about 0.8 cm long; erect when young and protected by bud scales. Female inflorescence is 0. 5-1.0 cm in fruit; scales with cuneate base and three more or less equal narrow erect lobes at the apex. Nutlet wings very narrow: up to a quarter as broad as the body (although recorded as up to half as broad as the body in Alaska-Hulten 1968).