Calflora, a 501c3 non-profit
Distribution by County   253    
Alnus rubra  Bong.
Oregon alder,   Red alder
Alnus rubra is a tree or shrub that is native to California, and also found elsewhere in North America and beyond.
Record Count by County

Alameda: 26 Lake: 1 San Francisco: 6 Siskiyou: 1
Contra Costa: 1 Marin: 207 San Mateo: 80 Sonoma: 74
Del Norte: 44 Mendocino: 98 Santa Clara: 3 Trinity: 4
Humboldt: 136 Monterey: 6 Santa Cruz: 112

Suggested Citation
Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals, including the Consortium of California Herbaria. [web application]. 2026. The Calflora Database [a non-profit organization]. Available: https://www.calflora.org/   (Accessed: 01/13/2026).