Vascular Plants - Betulaceae - Alnus:
Alnus rubra
Page Author: David Giblin
red alder, Oregon alder 
Blooms: March-April
Habit: tree
Duration: perennial
Origin: Native
Conservation Status: Abundant; of no concern.

Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska south to California, disjunct to the east in northern Idaho.
Habitat: Moist areas at low elevations.
Species Description:

General: Monoecious, deciduous trees to 25 m. tall, the bark thin, smooth and gray, the trunk up to 8 dm. thick; fresh wood tends to turn deep red.
Leaves: Leaves alternate, simple, the blades broadly elliptic or elliptic-ovate, 5-15 cm. long, usually acute at each end, wavy and irregularly denticulate, the margins slightly revolute, the upper surface deep green and glabrous, the lower surface rusty-gray and gland-dotted.
Flowers: Catkins developing before the leaves on growth of the previous season; staminate catkins clustered, pendulous, 5-12 cm. long; pistillate catkins cone-like, woody, ovoid-ellipsoid, 1.5-2 cm. long and 1 cm. thick, stout, thick peduncles under 1 cm. long.
Fruits: Nutlet with thin, membranous wings 1/5-1/2 as broad as the nutlet
Accepted Name:
Alnus rubra Bong.
Synonyms:
Alnus oregona Nutt.
Alnus oregona Nutt. var. pinnatisecta Starker
Alnus rubra Bong. var. pinnatisecta Starker

Treated in Flora of the PNW as:
Alnus rubra
Additional Resources:

PNW Herbaria Specimens: View list of all Alnus rubra specimens in the Consortium of Pacific Northwest Herbaria database.

WTU Herbarium Specimens: View list of Alnus rubra specimens in the WTU Herbarium database.

Washington Flora Checklist: Alnus rubra treatment.

E-Flora BC: Alnus rubra atlas page.

CalPhotos: Alnus rubra images.

USDA Plants Database: Alnus rubra.
Additional photographs of Alnus rubra:
(click on a thumbnail to view larger photo)

Clayton J. Antieau, 1997

Clayton J. Antieau, 1997

Ben Legler, 2004

Ben Legler, 2004

Ben Legler, 2004

Ben Legler, 2004

Ben Legler, 2004

Ben Legler, 2004

Clayton J. Antieau, 2004

Clayton J. Antieau, 2004

Clayton J. Antieau, 2004

Clayton J. Antieau, 2004

Clayton J. Antieau, 2002

M. R. Smith

H. Tim Gladwin, 1986

Bud Kovalchik

Bud Kovalchik

Bud Kovalchik

Bud Kovalchik

Bud Kovalchik

Bud Kovalchik

Bud Kovalchik

Bud Kovalchik

Bud Kovalchik

Ben Legler, 2006

Ben Legler, 2006

Ben Legler, 2006

Ben Legler, 2006

Richard Old

Al Dodson, 2007

Clayton J. Antieau, 2008

G. D. Carr, 2009

G. D. Carr, 2009

G. D. Carr, 2009

G. D. Carr, 2009

G. D. Carr, 2009

G. D. Carr, 2009

G. D. Carr, 2009

Paul Slichter, 2008

Paul Slichter, 2005

G. D. Carr, 2010

Susan McDougall, 2010

Daniel McNair , 2015

Susan McDougall, 2014
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Washington Native Plant Society
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