Stem: trunk < 35 m; bark smooth, gray to brown; twigs glabrous to fine-hairy, red-gray; lenticels small; winter buds stalked, 0--6-scaled.
Leaf: glabrous to fine-hairy; blade 3--15 cm, cordate to elliptic or diamond-shaped.
Staminate Inflorescence: 5--20 cm; bracts each subtending 3 flowers, 4 bractlets.
Pistillate Inflorescence: 5--20 mm; bracts each subtending 2 flowers, 4 fused bractlets.
Staminate Flower: sepals 4; stamens 1--4.
Pistillate Flower: sepals 0.
Fruit: many, in cone-like catkin, not enclosed by bract, winged, bracts 3 mm, woody, persistent.
Species In Genus: +- 25 species: northern hemisphere, South America.
Etymology: (Latin: alder)
Note: Root nodules contain nitrogen-fixing bacteria; wood used for interior finishing, to smoke fish, meats.
Jepson eFlora Author: John O. Sawyer, Jr.
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)Key to Alnus
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