Betula nana Betula nana Betula nana, the dwarf birch, is a species of birch in the family Betulaceae, found mainly in the tundra of the Arctic region. It is a monoecious shrub growing up to 1–1.2 m high. The bark is non-peeling and shiny red-copper colored. The leaves are rounded, 6–20 mm diameter, with a bluntly toothed margin. The leaves are a darker green on their upper surface. Leaf growth occurs after snow melt and become red in autumn. The wind-pollinated fruiting catkins are erect, 5–15 mm long and 4–10 mm broad. "Betula nana" is native to arctic and cool temperate regions
Mesoraphidiidae genera. Mesoraphidiidae are similar in overall appearance to modern snakefly species, having an elongated prothorax, giving a snake-like profile and from which the common name snakefly is derived. The family was likely tree-dwelling by nature, with larvae being active predators in trunks and branches. Female mesoraphidiids, where known and complete enough, have a long and densely annultated ovipositor which would have been used to lay eggs in crevices of bark. The family was restricted to the Northern Hemisphere, living in the warm temperate and paratropical forest belt that covered portions of Eurasia and North America. As currently described, Mesoraphidiidae contains