Sitka alder Betulaceae Alnus
viridis ssp. sinuata (Chaix) DC. ssp. sinuata (Regel) A. Löve & D. Löve symbol: ALVIS
Leaf: Alternate, simple, deciduous, ovate or oval, variable sized, 2 to 5 inches long, margins are sharply and doubly serrate or slightly lobed and serrated (but not revolute); green to yellow-green above and paler green below; thin and papery.
Flower: Species is monoecious but flowers are borne in unisexual aments (catkins); preformed male aments are long, slender, and pendent; female catkins are small and hang in long clusters from long stalks.
Fruit: A small semi-woody cone 1/2 to 1 inch long, persists through the winter; brown, seeds are tiny winged nutlets, shed in the fall.
Twig: Slender, zig-zag and spreading; orange-brown and sticky when young but turning gray and smooth with age; conspicuous lenticels; buds are slender and pointed with valvate scales, slightly stalked or sessile.
Bark: Gray to grayish green with warty lenticles, otherwise smooth.
Form: A thicket forming erect shrub or small tree, 20 to 40 feet tall and 5 to 10 inches in diameter. Common in avalanche tracks so they are often crooked or leaning.
Looks like: thinleaf alder - red alder - white alder - speckled alder
Additional Range Information: Alnus viridis ssp. sinuata is native to North America. Range may be expanded by planting. See states reporting Sitka alder.
External Links: USDAFS Additional Silvics - USDA Plants Database
All material © 2017 Virginia Tech Dept. of Forest Resources and Environmental Conservation; Photos and text by: John Seiler, Edward Jensen, Alex Niemiera, and John Peterson