Betula occidentalis

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Betula occidentalis
Foliage
Foliage
Conservation status
Secure
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Fagales
Family: Betulaceae
Genus: Betula
Subgenus: Betula
Species: B. occidentalis
Binomial name
Betula occidentalis
Hook.
Synonyms
  • B. fontinalis Sarg.

Betula occidentalis' (Water Birch) is a species of birch native to western North America, in Canada from Yukon east to western Ontario and southwards, and in the United States from eastern Washington east to western North Dakota, and south to eastern California, northern Arizona and northern New Mexico, and also possibly eastern Alaska (but see below). It typically occurs along streams in mountainous regions.[1]

It is a deciduous shrub or small tree growing to 10 m high, usually with multiple trunks. The bark is dark red-brown to blackish, and smooth but not exfoliating. The twigs are glabrous or thinly hairy, and odorless when scraped. The leaves are alternate, ovate to rhombic, 1-7 cm long and 1-4.5 cm broad, with a serrated margin and two to six pairs of veins, and a short petiole up to 1.5 cm long. The flowers are wind-pollinated catkins 2-4 cm long, the male catkins pendulous, the female catkins erect. The fruit is 2-3 cm long and 8–15 mm broad, composed of numerous tiny winged seeds packed between the catkin bracts.[1][2][3]

The identity of similar birches in eastern Alaska is disputed; some include them in B. occidentalis, while others regard them as hybrids between Betula neoalaskana and Betula glandulosa.[1]

[edit] References

  1. ^ a b c Flora of North America: Betula occidentalis
  2. ^ Plants of British Columbia: Betula occidentalis
  3. ^ Jepson Flora: Betula occidentalis