Flora of Scotts Creek Watershed
Alnus rubra - Red Alder
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Family Name: Betulaceae
Common Names: Red Alder, Oregon Alder
Origin: Native to California
Habitat: Stream banks and moist upland slopes below 1000m, found near the Pacific Coast.
Life Form and Duration: Perennial Tree, 15-30 m tall
Comments on overall growth: Erect, single trunk, clear of branches for 1/2 - 2/3 of height. Branches drooping and forming rounded narrow - broad crown in mature trees.
Bark and Stem Description: Thin, smooth, and light ashy gray to whitish, inner bark dark red, bark generally covered with lichen patches adding to mottled appearance.
Foliage Type: Deciduous
Foliage Description: Simple, alternate, broadly elliptic-ovate with acute tip and tapered to round base, 6-15 cm long. Conspicuously pinnate veins with midrib and major veins indented, when young leaves appear accordion folded. Leaf margins distinctly folded/rolled under and coarsely toothed (doubly serrated). Upper surfaces are dark green and hairless, under surfaces are pale green with prominent veins.
Infloresence Description: Male catkins: 2-4 per cluster at the end of branches, drooping, cylindrical, 10-15 cm long. Female catkins: 3-5 per cluster, terminal, erect, on stout stalks, 1-3 cm long, much like a mini cone.
Flowering Season: March-April
Fruit Description: Small but distinctively winged woody nutlet, many per catkin.
Plant Use: Foliage and bark used for wildlife browse.
Other Comments: Often becomes established on disturbed sites.