''Betula occidentalis'', the water birch or red birch, is a species of birch native to western

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, in

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

from

Yukon Yukon () is a Provinces and territories of Canada, territory of Canada, bordering British Columbia to the south, the Northwest Territories to the east, the Beaufort Sea to the north, and the U.S. state of Alaska to the west. It is Canada’s we ...

east to Northwestern

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

and southwards, and in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

from eastern Washington east to western

North Dakota North Dakota ( ) is a U.S. state in the Upper Midwest, named after the indigenous Dakota people, Dakota and Sioux peoples. It is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minneso ...

, and south to eastern

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

, northern

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

and northern

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

, and southwestern Alaska. It typically occurs along streams in mountainous regions,Flora of North America
''Betula occidentalis''
/ref> sometimes at elevations of and in drier areas than paper birch. Betula occidentalis 4

It is a

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

or small

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

growing to high, up to thick. It tends toward epicormic growth, with many small limbs sprouting from the trunk and causing the wood to be full of small knots. 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 A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

are alternate, ovate to rhombic, long and broad, with a serrated margin and two to six pairs of veins, and a short petiole up to long. The

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s are wind-pollinated

catkin A catkin or ament is a slim, cylindrical flower cluster (a spike), with inconspicuous or no petals, usually wind- pollinated ( anemophilous) but sometimes insect-pollinated (as in '' Salix''). It contains many, usually unisexual flowers, arra ...

s long, the male catkins pendulous, the female catkins erect. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

is long and broad, composed of numerous tiny winged seeds packed between the catkin bracts.Plants of British Columbia
''Betula occidentalis''
Jepson Flora
''Betula occidentalis''
/ref> The identity of similar birches in Alaska is disputed; some include them in ''B. occidentalis'', while others regard them as hybrids between '' Betula neoalaskana'' and '' Betula glandulosa''. A 2023 study sequenced chloroplast genomes of species from the genus ''Betula'' for phylogenetic analysis. Of the ''Betula'' species, ''B. occidentalis'' was most closely related to ''B. pendula'' purple rain and ''B. platyphylla.'' The foliage is browsed by sheep, goats, and birds; some small birds also consume the seeds. Some Plateau Indian tribes used water birch to treat pimples and sores. It is also a riverside tree found in western USA that reacts to water stress by becoming isohydric.

References

External links

* * {{Taxonbar, from=Q3926712 occidentalis Trees of Northern America Plants used in traditional Native American medicine Trees of continental subarctic climate Trees of humid continental climate Flora of Northern America

References

Further reading

External links