Burke: Populus trichocarpa vs. Populus angustifolia

	Populus trichocarpa	Populus angustifolia
	black cottonwood	narrow-leaved cottonwood
Habit	Rough-barked, dioecious tree up to 50 m. tall; buds large, the scales very resinous, glabrous.
Leaves	Leaves alternate, the blades fragrant, strongly resinous, the lower side distinctly paler than the upper, variable in shape, 5-15 cm. long and 3-9 cm. wide, broadest below the middle, pointed at the tip and usually rounded or truncate at the base, the surfaces usually glabrous; petioles terete, about half as long as the blade.
Flowers	Catkins drooping; the bracts subtending the flowers in the catkins lacerate-fringed; staminate catkins elongating to 2-3 cm, then deciduous; pistillate catkins at maturity 8-20 cm. long; stigmas 2, broadly dilated.
Fruits	Capsules rotund-ovate, 5-8 mm. long, sub-sessile.

	Populus trichocarpa	Populus angustifolia
Flowering time	April-June	April-May
Habitat	Streambanks, riparian zones, river corridors, and moist woods, from sea level to middle elevations in the mountains.	Riparian zones, from the foothills to the montane.
Distribution	Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east to Alberta and Wyoming. [WildflowerSearch map]	Occurring east of the Cascades crest in eastern Washington; Alberta to Nevada, east to the Great Plains. [WildflowerSearch map] [BONAP county map]
Origin	Native	Native
Conservation status	Not of concern	Not of concern
Sibling taxa	P. alba, P. angustifolia, P. ×canescens, P. deltoides, P. nigra, P. tremuloides	P. alba, P. ×canescens, P. deltoides, P. nigra, P. tremuloides, P. trichocarpa
Web links	Local floras: 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	Local floras: CA, 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

Populus angustifolia

black cottonwood

narrow-leaved cottonwood

Habit

Rough-barked, dioecious tree up to 50 m. tall; buds large, the scales very resinous, glabrous.

Leaves

Leaves alternate, the blades fragrant, strongly resinous, the lower side distinctly paler than the upper, variable in shape, 5-15 cm. long and 3-9 cm. wide, broadest below the middle, pointed at the tip and usually rounded or truncate at the base, the surfaces usually glabrous;

petioles terete, about half as long as the blade.

Flowers

Catkins drooping; the bracts subtending the flowers in the catkins lacerate-fringed; staminate catkins elongating to 2-3 cm, then deciduous; pistillate catkins at maturity 8-20 cm. long;

stigmas 2, broadly dilated.

Fruits

Capsules rotund-ovate, 5-8 mm. long, sub-sessile.