Betula cordifolia young bark is shiny brown with pale brown lenticels. The leaves are alternate, ovate, 6–12 cm long, and double-toothed. As the specific epithet suggests, the leaf base is generally cordate (heart-shaped), however this can be misleading as it is occasionally flat or rounded. The leaves are dotted with many resin glands and the buds are ovoid and blunt. The twigs are yellow-brown to dark-brown and are dotted with resin glands and gray lenticels. They lack the hairs found on "Betula papyrifera". The flowers are catkins, with pollen catkins 2–4 cm long and seed catkins 1–2 cm long. The seed catkins
Alnus viridis Alnus viridis Alnus viridis (green alder) is an alder distributed widely across the cooler parts of the Northern Hemisphere. It is a large shrub or small tree 3–12 m tall with smooth grey bark even in old age. The leaves are shiny green with light green undersurfaces, ovoid, 3–8 cm long and 2–6 cm broad. The flowers are catkins, appearing late in spring after the leaves emerge (unlike other alders which flower before leafing out); the male catkins are pendulous, 4–8 cm long, the female catkins 1 cm long and 0.7 cm broad when mature in late autumn, in clusters