Betula nana

Dwarf Birch
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Fagales
Family:	Betulaceae
Genus:	Betula
Subgenus:	Chamaebetula
Species:	B. nana
Binomial name
Betula nana L.

Betula nana (Dwarf Birch) is a species of birch in the family Betulaceae, found mainly in the tundra of the Arctic region.

Description

Diapensia lapponica with a branch of dwarf birch, Nunavut, July 1996

It is a shrub growing to 1-1.2 m high. The bark is non-peeling and shiny red-copper colored.^[1] The leaves are rounded, 6-20 mm diameter, with a bluntly toothed margin. They become red in the autumn. The fruiting catkins are erect, 5-15 mm long and 4-10 mm broad.

Distribution

B. nana is native to arctic and cool temperate regions of northern Europe, northern Asia and northern North America and it will grow in a variety of conditions.It can be found in Greenland. Outside of far northern areas, it is usually found only growing in mountains above 300 m, up to 835 m in Scotland and 2200 m in the Alps. Its eastern range limit is on Svalbard, where it is confined to warm sites.

Ecology

There are two subspecies:

• Betula nana subsp. nana. Canada (Baffin Island), Greenland, northern Europe (south to the Alps at high altitudes), northwestern Asia. Young twigs hairy, but without resin; leaves longer (to 20 mm), usually as long as broad.
• Betula nana subsp. exilis. Northeastern Asia, northern North America (Alaska, Canada east to Nunavut). Young twigs hairless or only with scattered hairs, but coated in resin; leaves shorter (not over 12 mm long), often broader than long.

References

1. ^ Ewing, Susan. The Great Alaska Nature Factbook. Portland: Alaska Northwest Books, 1996.

• Trees for Life: Species profile and Reference list
• Flora of North America: Betula nana
• Betula nana Distribution map
• Conservation Genetics and Population History of Betula nana etc., in Svalbard