Betula pendula |
Betulaceae subfam. betuloideae |
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bouleau pleureur, European birch, European weeping birch, European white birch, silver birch, weeping birch |
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Habit | 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. |
thin, close or exfoliating in thin sheets, becoming thicker and frequently furrowed or broken in age; lenticels often present, prominent, sometimes becoming greatly expanded horizontally.; bark and wood strongly tanniferous. |
Branches | pendulous; twigs glabrous, usually dotted with small resinous glands. |
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Leaves | 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. |
3-ranked, occasionally nearly 2-ranked. |
Staminate flowers | perianth of 4(–6) sepals, well defined, minute, membranaceous. |
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Pistillate flowers | 2–3 per scale, scales arranged in conelike catkins; perianth not obvious; ovules with 1 integument. |
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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. |
1–4 cm, conelike, composed of many scales; scales either persistent or deciduous with fruits, crowded, small, woody or leathery. |
Fruits | tiny samaras, lateral wings 2, membranous, sometimes reduced to ridges; pericarp thin, leathery. |
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Samaras | with wings much broader than body, broadest near center, extended beyond body apically. |
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Trunks | and branches terete. |
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Young | twigs and buds often covered with small to large, resinous glands; pith triangular in cross section. |
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2n | = 28, 56. |
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Betula pendula |
Betulaceae subfam. betuloideae |
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Phenology | Flowering late spring. | |
Habitat | Abandoned plantings, roadsides, edges of bogs, waste places | |
Elevation | 0–350 m (0–1100 ft) | |
Distribution |
CT; MA; NH; NY; OH; PA; VT; WA; BC; MB; ON; Europe; Asia
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Primarily boreal and cool temperate zones of Northern Hemisphere |
Discussion | 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. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Genera 2, species 60 (2 genera, 26 species in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 3. | FNA vol. 3. |
Parent taxa | Betulaceae > subfam. Betuloideae > Betula | Betulaceae |
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | B. verrucosa | |
Name authority | Roth: Tent. Fl. Germ. 1: 405. (1788) | Koehne: Deut. Dendrol. 106, 1893 (as Betulae) |
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