Alnus glutinosa
Alnus rubra
European black alder
red alder
blades ovate, 75–130 × 51–93 mm; firm, bases obtuse or truncate;
margins folded under; coarse teeth rounded or triangular, 3–7 mm (sometimes deeper and forming shallow lobes), finely serrulate with low; blunt teeth;
secondary veins 9–13 on each side;
tips obtuse or weakly acuminate;
surfaces abaxially dry or seldom resinous, pubescent (sometimes late in season only on and around veins; blades becoming glabrate), adaxially glabrous;
petioles 12–22(30) mm, glabrous.
cylindrical, rounded, resinous;
scales 2–3, valvate; each scale as long as bud, stalked.
of both sexes develop in summer; open the following spring before leaves unfurl; male catkins to 12 cm × 7 mm.
ovoid, 15–24 × 9–14 mm, peduncles of terminal cones 5–13 mm long, 1.0–1.8 mm thick;
fruit wings 0.2–0.6 mm wide; opaque, grading into body of fruit.
Alnus glutinosa
Alnus rubra
Riverbanks, streambanks, bogs, moist forests. Flowering Feb–Apr. 0–1600 m. BW, Casc, CR, Est, Sisk, WV. CA, ID, WA; north to AK. Native.
Red alder is the most important commercial hardwood of the Pacific Northwest. The wood is used for furniture and cabinetry. Red alder is often the first species to colonize following logging of moist conifer forests. When red alder colonizes such sites, it often prevents the establishment of Douglas-fir. Trees with lobed leaves are met with occasionally.
Alan Whittemore
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
