Betula populifolia multiple trunks branching off of an old stump. The leaves are 5-7.5 cm long by 4–6 cm wide, alternately arranged, ovate, and tapering to an elongated tip. They are dark green and glabrous above and paler below, with a coarsely serrated margin. The bark is chalky to grayish white with black triangular patches where branch meets trunk. It is most easily confused for the paper birch ("Betula papyrifera") by means of its bark; it is smooth and thin but does not readily exfoliate like paper birch does. The flowers are wind-pollinated catkins 5–8 cm long, the male catkins pendulous and
Alnus cordata with a very long season in leaf, from April to December in the Northern Hemisphere; they are alternate, cordate (heart-shaped), rich glossy green, 5–12 cm long, with a finely serrated margin. The slender cylindrical male catkins are pendulous, reddish and up to 10 cm long; pollination is in early spring, before the leaves emerge. The female catkins are ovoid, when mature in autumn 2–3 cm long and 1.5–2 cm broad, dark green to brown, hard, woody, and superficially similar to some conifer cones. The small winged seeds disperse through the winter, leaving the old woody, blackish 'cones' on the tree