Page author: David Giblin
Alnus incana
mountain alder

Distribution: Occurring east of the Cascades crest in Washington; Alaska south to New Mexico, also in the north-central and northeastern region of North America.

Habitat: Moist places, streamside, low to high elevations.

Flowers: March-May

Origin: Native

Conservation Status: Not of concern


Monoecious, deciduous shrubs 2 to 10 m. tall, the bark grayish-brown to reddish, the new growth usually downy-puberulent.


: Leaves alternate, simple, the blades broadly elliptic to ovate-oblong, 3-7 cm. long, rounded at the base and usually obtuse at the tip, the margins wavy and denticulate, the upper surface green, often glabrous, the lower surface pale, usually pubescent.


Catkins developing before the leaves on growth of the previous season; staminate catkins clustered, pendulous, 3-10 cm. long, the flowers consisting of 4 subsessile anthers; pistillate catkins cone-like, ellipsoid-ovoid, 9-13 mm. long, the peduncles stout, short.


Nutlet thin-margined but without a true wing.

Accepted Name:
Alnus incana (L.) Moench
Publication: Methodus. 424. 1794.

Synonyms & Misapplications:
(none provided)
ssp. tenuifolia – mountain alder
Additional Resources:

PNW Herbaria: Specimen records of Alnus incana in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Alnus incana checklist entry.

E-Flora BC: Alnus incana atlas page.

CalPhotos: Alnus incana photos.

USDA Plants: Alnus incana information.

36 photographs:
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