Shrub or dwarf shrub. 0.2–0.8 m (7–30 in.).
Small, greenish to brownish, lacking perianth. Inflorescences dense, pendent catkins formed by numerous, 3-flowered cymes. Male and female flowers in separate inflorescences.
Fairly small, more or less orbicular (roundish), thick, hairless, margins crenate (with rounded teeth). Autumn colour yellow, orange, or red.
Roundish, small, dark brown, scales hairy-edged.
Small, winged achene.
Bogs, swamps, fens. In Northern Finland also forests and mountain heaths.
May–June. Flowers when coming into leaf.
The genus Betula comprises some 40 species, both trees, shrubs, and dwarf shrubs. The trunks of birches are covered with white or darkish, often papery bark. Birches flower when coming into leaf in the spring. The small flowers are unisexual, the inflorescence a catkin-like, dense compound cyme.
In Southern Finland, dwarf birch is wholly a mire plant thriving on many different mire types. It hybridises with both silver birch (B. pendula) and downy birch (B. pubescens). The hybrids are usually taller than pure dwarf birches and their leaves are larger. Dwarf birch used to be an important source for fuel in Lapland as it burns even when fresh. It is also a constituent part of the vivid autumn colours of the Lappish moorlands.
Dwarf Birch, Betula nana - Trees and shrubs - NatureGate