Burke: Betula pendula vs. Betula occidentalis

	Betula pendula	Betula occidentalis
	European weeping birch	red birch, river birch, water birch
Habit	Monoecious, deciduous trees to 25 m., trunks usually several, the crowns spreading; bark of mature trees creamy to silvery-white, smooth, peeling in long strips; lenticels dark; branches pendulous, twigs glabrous, dotted with small, resinous glands.	Monoecious, deciduous shrubs or small trees to 8 m. tall, the young twigs with crystalline glands, the older wood smooth and coppery to reddish-brown, not peeling.
Leaves	Leaf blades broadly ovate to rhombic, 3-7 cm. long and 2.5-5 cm. wide, the base wedge-shaped, the margins sharply double serrate, the tip acuminate, surfaces glabrous to sparsely pubescent.	Leaves alternate, usually glandular, the blades usually ovate to suborbicular, the tip rounded to acute, the base usually rounded, the margins sharply once- or twice-serrate.
Flowers	Staminate catkins 3 per scale, pendulous; pistillate catkins 3 per scale, erect, cylindric, 2-3.5 cm. long, the scales 3-lobed, the lateral lobes broad and rounded, much longer that the central lobe.	Staminate catkins elongate and pendulous, 1-4 per cluster; pistillate catkins erect, 2-4 cm. long and 4-10 mm. thick, the naked flowers subtended by a 3-lobed bract, puberulent and with marginal hairs.
Fruits	Samaras with wings much broader than bodies, broadest in the center.	Samara, the wings about as broad as the pubescent nutlet.

	Betula pendula	Betula occidentalis
Flowering time	April-May	February-June
Habitat	Disturbed areas associated with urban and suburban development where the trees escape from cultivation.	Moist areas, streambanks at low elevations.
Distribution	Occurring chiefly west of the Cascades crest in Washington; southern British Columbia to Oregon; also in northeastern North America. [WildflowerSearch map] [BONAP county map]	Occurring chiefly east of the Cascades crest in Washington; Alaska to California, east in Canada to Ontario, east in the U.S. to the Rocky Mountains and northern Great Plains. [WildflowerSearch map] [BONAP county map]
Origin	Introduced from Eurasia	Native
Conservation status	Not of concern	Not of concern
Sibling taxa	B. glandulosa, B. occidentalis, B. papyrifera, B. populifolia, B. pubescens, B. pumila, B. ×utahensis	B. glandulosa, B. papyrifera, B. pendula, B. populifolia, B. pubescens, B. pumila, B. ×utahensis
Web links	Local floras: BC, OR, WA 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: 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

Betula occidentalis

European weeping birch

red birch, river birch, water birch

Habit

Monoecious, deciduous trees to 25 m., trunks usually several, the crowns spreading; bark of mature trees creamy to silvery-white, smooth, peeling in long strips; lenticels dark; branches pendulous, twigs glabrous, dotted with small, resinous glands.

Monoecious, deciduous shrubs or small trees to 8 m. tall, the young twigs with crystalline glands, the older wood smooth and coppery to reddish-brown, not peeling.

Leaves

Leaf blades broadly ovate to rhombic, 3-7 cm. long and 2.5-5 cm. wide, the base wedge-shaped, the margins sharply double serrate, the tip acuminate, surfaces glabrous to sparsely pubescent.

Leaves alternate, usually glandular, the blades usually ovate to suborbicular, the tip rounded to acute, the base usually rounded, the margins sharply once- or twice-serrate.

Flowers

Staminate catkins 3 per scale, pendulous; pistillate catkins 3 per scale, erect, cylindric, 2-3.5 cm. long, the scales 3-lobed, the lateral lobes broad and rounded, much longer that the central lobe.

Staminate catkins elongate and pendulous, 1-4 per cluster; pistillate catkins erect, 2-4 cm. long and 4-10 mm. thick, the naked flowers subtended by a 3-lobed bract, puberulent and with marginal hairs.

Fruits

Samaras with wings much broader than bodies, broadest in the center.

Samara, the wings about as broad as the pubescent nutlet.

Betula pendula

Betula occidentalis

Flowering time

April-May

February-June

Habitat

Disturbed areas associated with urban and suburban development where the trees escape from cultivation.

Moist areas, streambanks at low elevations.

Distribution

Occurring chiefly west of the Cascades crest in Washington; southern British Columbia to Oregon; also in northeastern North America.

[WildflowerSearch map]

[BONAP county map]

Occurring chiefly east of the Cascades crest in Washington; Alaska to California, east in Canada to Ontario, east in the U.S. to the Rocky Mountains and northern Great Plains.

[WildflowerSearch map]

[BONAP county map]

Origin

Introduced from Eurasia

Native

Conservation status

Not of concern

Sibling taxa