Alnus sinuata (syn. A. viridis subsp. sinuata) Betulaceae
Sitka Alder, Wavy Leaf Alder
- Deciduous, thicket forming shrub or small tree, often with several trunks, 20-35 ft (9-10 m) tall, taller at lower elevations. Twigs glossy light brown to yellow-brown, at first pubescent and dotted with glands, later smooth with conspicuous lenticels, buds are sessile (i.e., without a stalk). Bark is reddish-brown, gray or grayish-green, smooth, thin. Leaves alternate, simple, 4-13 cm long, 4-7.5 cm wide, ovate to ovate-oval, thin, papery, doubly serrate to slightly lobed, green to yellowish-green above, paler and smooth below.
- Sun part shade. A pioneer species, and is adapted to soils that are too poor for growth of other trees, but best on moist sites. Its ability to fix nitrogen allows it to invade soils with low fertility, such as those recently exposed by glaciers or avalanches.
- Hardy to USDA Zone 2 Native to a large area, from the Yukon and western and southern Alaska southward to northern California and eastward to southwestern Alberta and western Montana, also northeastern Oregon. Usually found above 3,000 ft (900 m) elevation, although it also grows in the snowy coastal tundra of Alaska. Sometimes called "slide alders", since they form almost impenertrable thickets in avalanche swaths in the Cascades.
- Recent studies have shown that Sitka Alder is part of a circumpolar alder group (Alnus viridis) distributed across America, Europe, and Asia. This species has been separated into two subspecies, namely (1) A. viridis supsp. crispa - Green Alder - northern North America, including the Northwest, and (2) A. viridis subsp. sinuata - Sitka alder.
- sinuata: strongly wavy margin
- Oregon State Univ. campus: south of Peavy Hall, native plants area.