Betula pendula |
Betula pumila |
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bouleau pleureur, European birch, European weeping birch, European white birch, silver birch, weeping birch |
bog birch, bouleau nain, dwarf birch, glandular birch, low birch, scrub birch, swamp birch |
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Habit | Trees, to 25 m; trunks usually several, crowns spreading. | Shrubs, coarse, irregular, or spreading, to 4 m. |
Bark | of mature trunks and branches creamy to silvery white, smooth, exfoliating as long strands; lenticels dark, horizontally expanded. |
dark reddish brown, smooth, close; lenticels pale, inconspicuous. |
Branches | pendulous; twigs glabrous, usually dotted with small resinous glands. |
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Twigs | without taste and odor of wintergreen, glabrous to moderately pubescent, with scattered small resinous glands, especially near nodes. |
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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. |
blade elliptic, obovate, or nearly orbiculate (to sometimes reniform) with 2–6 pairs of lateral veins, 2.5–5(–7) × 1–5 cm, base cuneate to rounded, margins crenate to dentate, apex usually broadly acute or obtuse to rounded; surfaces abaxially glabrous or slightly pubescent to heavily velutinous or tomentose, often with scattered 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. |
erect, cylindric, 0.8–1.5(–2) × 0.8–1 cm, shattering with fruits in fall; scales glabrous to pubescent, lobes diverging slightly distal to middle, central lobe narrow, elongate, lateral lobes shorter and broader, extended. |
Samaras | with wings much broader than body, broadest near center, extended beyond body apically. |
with wings slightly narrower than body, broadest near center, not extended beyond body apically. |
2n | = 28, 56. |
= 56. |
Betula pendula |
Betula pumila |
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Phenology | Flowering late spring. | Flowering late spring. |
Habitat | Abandoned plantings, roadsides, edges of bogs, waste places | Bogs, calcareous fens, wooded swamps, muskegs, lake shores |
Elevation | 0–350 m [0–1100 ft] | 0–700 m [0–2300 ft] |
Distribution |
CT; MA; NH; NY; OH; PA; VT; WA; BC; MB; ON; Europe; Asia
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CA; CO; CT; IA; ID; IL; IN; KS; MA; ME; MI; MN; MT; ND; NE; NJ; NY; OH; OR; PA; SD; VT; WA; WI; WY; AB; BC; MB; NB; NF; NS; NT; ON; PE; QC; SK; YT; SPM
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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.) |
Betula pumila is sometimes treated (in part) as a variety of B. glandulosa Michaux, to which it is related at a subgeneric or sectional level. On the basis of morphology, however, it forms a cohesive and distinct entity (J. J. Furlow 1984). The two main varieties into which B. pumila is often divided (a more southern B. pumila var. pumila, with mostly pubescent, glandless leaves, and a more northern B. pumila var. glandulifera, with less pubescent, gland-bearing leaves) may represent geographic races; these are not well marked, however, and they do not hold up well when the complex is examined as a whole. The Ojibwa used Betula pumila medicinally as a gynecological aid and as a respiratory aid (D. E. Moerman 1986). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 3. | FNA vol. 3. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | B. verrucosa | B. borealis, B. glandulifera, B. glandulosa var. glandulifera, B. glandulosa var. hallii, B. hallii, B. nana var. glandulifera, B. pubescens subsp. borealis, B. pumila var. glabra, B. pumila var. glandulifera, B. pumila var. renifolia |
Name authority | Roth: Tent. Fl. Germ. 1: 405. (1788) | Linnaeus: Mant. Pl., 124. (1767) |
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