(Upload on December 15 2014) [ 日本語 | English ]

Betula nana L.

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

Betula L. (カバノキ) in Alaska
Himekamba (ヒメカンバ, 姫樺), dwarf birch
Lifeform: dwarf shrub
Distribution: arctic and cool temperate regions
Habitat: widespread in arctic tundra
Leaf: orbicular, with truncate or cordate base, often broader than long, crenulated all around
Seed dispersal: wind
Chromosome number: 2n = 28
ssp. nana: young twigs hairy without resin, leaves longer (to 20 mm), usually as long as broad, not in AK
ssp. exilis (Sukaczev) Hultén: young twigs hairless or with only scattered hairs with coated in resin, leaves shorter (< 12 mm long), often broader than long

Synonyms: Betula exilis Sukaczev, Betula nana var. sibirica Ledeb.

ssp. perfiljevii (V. N. Vassil.) A. Love et D. Love, discarded

B. glandulosa Michx., resin birch or shrub birch
Leaf: obovate, with cuneate toothless base

Betula nana in Alaska

Birch1 Birch2 Birch3
[1-3] ssp. exilis in a tussock-shrub tundra near Toolik Lake LTER Station, on August 3 2014.