Page authors: Don Knoke, David Giblin
Alnus rhombifolia
white alder

Distribution: Occurring chiefly east of the Cascades crest in Washington; Washington to California and Nevada, east to Idaho.

Habitat: Near streams at low elevations.

Flowers: January-April

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind


Monoecious, deciduous small trees 5-20 m. tall, the old bark light-colored, the new growth puberulent.


Leaves alternate, simple, the blades elliptic or oblong-rhombic, 4-8 cm. long, acute to rounded at each end, finely to coarsely once- or twice-serrate, not wavy, hairy at least beneath, the upper surface deeper green.


: Catkins developing before the leaves on growth of the previous season; staminate catkins slender, pendulous, 4-8 cm. long, the stamens usually 2 per flower; pistillate catkins cone-like, woody, 10-15 mm. long, on stout peduncles often as long as the catkin.


Nutlet thin-margined but without a true wing.

Accepted Name:
Alnus rhombifolia Nutt.
Publication: N. Amer. Sylv. 1: 49. 1842.

Synonyms & Misapplications:
Alnus rhombifolia Nutt. var. bernardina Munz & I.M. Johnst.
Additional Resources:

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

WA Flora Checklist: Alnus rhombifolia checklist entry

OregonFlora: Alnus rhombifolia information

E-Flora BC: Alnus rhombifolia atlas page

CalPhotos: Alnus rhombifolia photos

61 photographs:
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