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.
Description.
It is a monoecious shrub growing up to high. The bark is non-peeling and shiny red-copper colored. The leaves are rounded, 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, long and broad.
Distribution.
"Betula nana" is native to arctic and cool temperate regions of Greenland, Iceland, northern Europe, northern Asia and northern North America and it will grow in a variety of conditions. Outside of far northern areas, it is usually found growing only in mountains above , up to in Scotland and in the Alps. Its northern range limit is on Svalbard, where it is confined to warm sites. In the UK "Betula nana" is at its southern range limit, with many populations having declined significantly in recent decades. In southern Sweden the occurrence of "Betula nana" in Sund, Ydre is deemed a glacial relict.
In general, it favors wet but well-drained sites with a nutrient-poor, acidic soil which can be xeric and rocky. "B. nana" has a low tolerance for shade.
Ecology.
There are two subspecies:
Genome.
The genome of "B. nana" has been sequenced.