Alnus incana subsp. tenuifolia
Mountain alder, Mountain Alder
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Family: Betulaceae · Type: Shrub / Tree · Native
Alnus incana subsp. tenuifolia (Mountain alder) is a native California shrub / tree in the Betulaceae family, recognized by clearly distinguished by shrub habit, high elevation, and indented leaf veins.
Mountain alder is a native shrub found in the Klamath Ranges, northern Coast Ranges, California Ranges, and Sierra Nevada Highlands in wet places at elevations of 1,200 to 2,400 meters. Flowering from April to June, this plant produces small clustered flowers with yellow-green tones. Growing with multiple trunks up to 9 meters tall, the shrub develops a distinctive branching structure. Its leaves are thick with rounded to slightly heart-shaped bases, dark green on the upper surface with indented midribs and major veins, and yellow-green underneath. The shrub creates dense thickets in moist mountain environments, often near streams and wetland edges.
Identification and appearance
Key characters: 3 sympatric species; clearly distinguished by shrub habit, high elevation, and indented leaf veins
Habitat and range
Habitat: Wet places
Elevation: 1200-2400 m
California counties: San Diego, Siskiyou, Plumas, Fresno, Alpine, Shasta, Nevada, Mono, El Dorado, Tuolumne, Humboldt, Trinity, Sierra, Tehama, Madera, Placer, Tulare, Glenn, Butte, Lassen, Mendocino, Inyo, Colusa, Lake, Amador, Yuba
Outside California: to Alaska, western Canada, Wyoming, New Mexico
Bloom period
Alnus incana subsp. tenuifolia blooms Apr-Jun.
How to tell it apart
vs Corylus: Alnus has tiny winged seeds from persistent woody cones; Corylus has large nuts in papery husks.; vs Populus: Alnus has woody persistent cone-like catkins; Populus has fluffy cottony seeds from capsules.; vs Quercus: Alnus has woody cone-like catkins and toothed leaves; Quercus has acorns in caps and lobed leaves.; vs Betula: Alnus has woody cones that persist after seeds drop; Betula catkins disintegrate completely, releasing papery scales with seeds.; vs Ulmus: Alnus has woody cone-like catkins; Ulmus has flat, round, papery winged fruits.
Frequently asked questions
Is Alnus incana subsp. tenuifolia native to California?
Yes. Alnus incana subsp. tenuifolia is native to California (recorded as native).
When does Alnus incana subsp. tenuifolia bloom?
Alnus incana subsp. tenuifolia blooms Apr-Jun.
Where in California does Alnus incana subsp. tenuifolia grow?
Alnus incana subsp. tenuifolia occurs in San Diego, Siskiyou, Plumas, Fresno, Alpine, Shasta, Nevada, Mono and other counties, at elevations of 1200-2400 m.
What plant family does Alnus incana subsp. tenuifolia belong to?
Alnus incana subsp. tenuifolia is in the Betulaceae family, genus Alnus.
What habitat does Alnus incana subsp. tenuifolia grow in?
Alnus incana subsp. tenuifolia grows in Wet places.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.