Page authors: Don Knoke, David Giblin
Acer glabrum
Rocky Mountain maple

Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains and Great Plains.

Habitat: Moist woods from sea level to mid-elevations in the mountains.

Flowers: April-June

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern


Shrub or small tree 1-10 m. tall; stems glabrous, the bark grayish to reddish-purple.


Leaves opposite, glabrous to sparsely glandular-puberulent, 2-14 cm. long and nearly as broad, cordate, palmately 3-5 lobed, coarsely serrate, paler on the lower surface.


Plants monoecious to dioecious, staminate flowers with only rudiments of a pistil, but pistillate flowers with well-developed, though not always fertile, stamens; flowers about 8 mm. broad, in flat-topped clusters in the leaf axils; sepals usually 5; petals equal in size and number, or lacking; stamens usually 10, inserted on the outer edge of a lobed disk; styles and stigmas 2; ovary superior, 2-celled.


Samaras 2.5-3 cm. long, the wings not divergent.

Accepted Name:
Acer glabrum Torr.
Publication: Ann. Lyceum Nat. Hist. New York ii. 172 1828. 1828.

Synonyms & Misapplications:
(none provided)
Additional Resources:

PNW Herbaria: Specimen records of Acer glabrum in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Acer glabrum checklist entry.

OregonFlora: Acer glabrum information.

E-Flora BC: Acer glabrum atlas page.

CalPhotos: Acer glabrum photos.

USDA Plants: Acer glabrum information.

58 photographs:
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