Betula pumila
Betula papyrifera
bog birch, bouleau nain, dwarf birch, glandular birch, low birch, scrub birch, swamp birch
bouleau blanc, bouleau à papier, canoe birch, paper birch, western paper birch, white birch
of young trunks and branches dark reddish brown, smooth, in maturity creamy to chalky white or pale to (infrequently) dark brown, readily exfoliating in paper-thin sheets;
lenticels pale, horizontal, in maturity dark, much expanded, horizontal.
without taste and odor of wintergreen, glabrous to moderately pubescent, with scattered small resinous glands, especially near nodes.
without strong odor and taste of wintergreen, slightly to moderately pubescent, infrequently with scattered, small, 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.
blade ovate with 9 or fewer pairs of lateral veins, 5–9(–12) × 4–7 cm, base rounded, cuneate, or truncate, margins sharply to coarsely or irregularly doubly serrate or serrate-dentate, apex acute to short-acuminate;
surfaces abaxially sparsely to moderately pubescent, often velutinous along major veins and in vein axils, covered with minute, resinous glands.
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.
pendulous, cylindric, 2.5–5 × 0.6–1.2 cm, readily shattering with fruits in late fall;
scales pubescent to glabrous, lobes diverging at or proximal to middle, central lobe narrowly elongate, obtuse, lateral lobes about equal in length to central lobe but several times broader, strongly divergent, held nearly at right angles to axis.
with wings slightly narrower than body, broadest near center, not extended beyond body apically.
with wings as broad as or slightly broader than body, extended nearly beyond body apically.
= 56.
= 56, 70, 84.
Betula pumila
Betula papyrifera
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.)
Betula papyrifera is a well-known tree of the northern forest with its paper-thin, white, peeling bark. The bark, which has a high oil content and is consequently waterproof, was used for a wide variety of building and clothing purposes by the American Indians, including the covering of the familiar birch bark canoe. It is still used for various purposes, including basketmaking, in Canada and Alaska. Variants having more or less close, dark brown bark (B. papyrifera var. commutata) occur locally throughout the wide range of this species; this characteristic appears to be largely environmentally caused. The species is an important successional tree, coming up readily after fires, logging, or the abandonment of cultivated land. The relatively soft, whitish wood is used extensively for such items as clothespins, spools, ice cream sticks, and toothpicks, as well as for pulpwood for paper.
Betula papyrifera is the state tree of New Hampshire.
Native Americans use Betula papyrifera medicinally in enemas, to shrivel the womb, to alleviate stomach cramps and pain, and as a tonic (D. E. Moerman 1986).
Betula ×sandbergii Britton is a fairly common hybrid, occurring where the ranges of the parents (B. papyrifera Marshall and B. pumila Linnaeus) come into contact. In most vegetative features it is intermediate between the parental conditions (K. E. Clausen 1963; C. O. Rosendahl 1928).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
BC, 
OR, 
WA - Local Web sites:
CalFlora, CalPhotos, 
Flora NW, 
Go Botany, 
IL Wildflowers, 
KS Wildflowers, 
MI Flora, 
MN Wildflowers, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
