Common Birch

The Eurasian weeping birch ( Betula pendula ) is extensively cultivated throughout the temperate range of the flora, and it has been known to persist or to become locally naturalized in several areas, particularly in the Northeast. In vegetative features it resembles B . populifolia Marshall, to which it is closely allied; it can easily be distinguished from the latter by its peeling bark, as well as by its mostly pubescent leaves with somewhat shorter, acuminate apices.

May easily be confused with Betula platyphylla; however, in that species, the branches are not pendulous and the wings of the nutlet are about as wide as the nutlet. The name B. alba Linnaeus, nom. rej. prop., has been widely and persistently misapplied in the sense of B. pendula; the lectotype of B. alba belongs to the species currently known as B. pubescens Ehrhart, which does not occur in China.

Trees , to 25 m; trunks usually several, crowns spreading. Bark of mature trunks and branches creamy to silvery white, smooth, exfoliating as long strands; lenticels dark, horizontally expanded. Branches pendulous; twigs glabrous, usually dotted with small resinous glands. Leaf blade broadly ovate to rhombic with 5--18 pairs of lateral veins, 3--7 × 2.5--5 cm, base cuneate, rarely truncate, margins coarsely and sharply doubly serrate, apex acuminate; surfaces abaxially glabrous to sparsely pubescent, covered with minute, resinous glands. Infructescences erect to nearly pendulous, cylindric, 2--3.5 × 0.6--1 cm, shattering with fruits in fall; scales adaxially sparsely pubescent, lobes diverging at middle, central lobe obtuse, much shorter than lateral lobes, lateral lobes broad, rounded, extended. Samaras with wings much broader than body, broadest near center, extended beyond body apically. 2 n = 28, 56.

Trees to 25 m tall; bark grayish white, exfoliating in sheets. Branches usually pendulous, dark brown, slender, glabrous, shiny; branchlets brown, slender, glabrous, sparsely resinous glandular or not. Petiole slender, 2-3 cm; leaf blade triangular-ovate or rhombic-ovate, 3-7.5 × 1.5-6 cm, abaxially densely resinous punctate, adaxially glabrous, base truncate, broadly cuneate, or cuneate, margin coarsely or incised doubly serrate, apex acuminate or caudate-acuminate; lateral veins 6-8 on each side of midvein. Female inflorescence oblong or oblong-cylindric, 1-3.3 cm × 8-10 mm; peduncle pendulous, 1-2 cm; bracts 5-6 mm, densely pubescent, ciliate, 3-lobed, middle lobe ovate or triangular-ovate, lateral lobes recurved, slightly longer than middle lobe. Nutlet obovate-elliptic, ca. 2 × 1 mm, sparsely pubescent, with membranous wings slightly longer than and ca. 2 × as wide as nutlet. Fl. Jun-Jul, fr. Jul-Aug. 2n = 28, (42), 56.

B.C., Man., Ont.; Conn., Mass., N.H., N.Y., Ohio, Pa., Vt., Wash.; Europe; Asia.

N Xinjiang (Altay Shan) [Kazakhstan, Mongolia, Russia (W Siberia); Europe]

Flowering late spring.

Abandoned plantings, roadsides, edges of bogs, waste places; 0--350m.

Temperate broad-leaved forests; 500-2300 m.

Betula verrucosa Ehrhart

Betula verrucosa Ehrhart.