Burke: Populus fremontii vs. Populus trichocarpa

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

Populus fremontii

Populus trichocarpa

black 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.