Betula neoalaskana

Sargent

J. Arnold Arbor. 3: 206. 1922.

Common names: Resin birch paper birch
Endemic
Basionym: Betula alaskana Sargent Bot. Gaz. 31: 236. 1901,
Synonyms: Betula papyrifera subsp. humilis (Regel) Hultén Betula papyrifera var. humilis (Regel) Fernald & Raup Betula papyrifera var. neoalaskana (Sargent) Raup Betula resinifera
Treatment appears in FNA Volume 3.

Trees, to 25 m, crowns narrow. Bark of young trunks and branches reddish-brown, when mature becoming pinkish white to light red (starkly white in interior Alaska; D. F. Murray, pers. comm.), smooth, exfoliating in thin sheets. Twigs glabrous, covered with conspicuous resinous glands. Leaf-blade deltate-ovate with 5–18 pairs of lateral-veins, 3–8 × 2–6 cm, base rounded or broadly cuneate, margins coarsely doubly serrate, apex long-acuminate; surfaces abaxially glabrous to sparsely pubescent, pubescent along major veins and in vein-axils, covered with small resinous glands. Infructescences pendulous, cylindric, 2–4 × 0.8–1.2 cm, shattering with fruits in fall; scales glabrous, margins ciliate, lobes diverging distal to middle, central lobe narrower and equal to or slightly shorter than lateral lobes, lateral lobes broadly angular, extended. Samaras with wings broader than body, broadest near summit, extended beyond body apically. 2n = 28.


Phenology: Flowering late spring.
Habitat: Rocky or peaty slopes, bog margins, sandhills, open woods
Elevation: 100–1200 m

Distribution

V3 962-distribution-map.gif

Alta., B.C., Man., N.W.T., Ont., Sask., Yukon, Alaska.

Discussion

Betula neoalaskana belongs to a circumpolar complex including B. pendula Roth and B. populifolia Marshall (but not B. papyrifera Marshall, with which it has sometimes erroneously been merged). It is most closely related to the Asian members of this group, including B. japonica Siebold, B. mandshurica (Regel) Nakai, and B. platyphylla Sukaczev (T. C. Brayshaw 1976). The species was formerly widely known by the name B. resinifera (Regel) Britton, but that name has been shown to be illegitimate (B. Boivin 1967–1979, 15: 414–418; J. R. Dugle 1969). The name was based on a mixture of Siberian and North American material and has never been lectotypified.

Betula neoalaskana Sargent is known to hybridize with B. papyrifera Marshall, producing B. ×winteri Dugle, and with B. glandulosa, producing B. ×uliginosa Dugle.

Selected References

None.

Lower Taxa

None.

"broadest" is not a number. "broader" is not a number.

... more about "Betula neoalaskana"
John J. Furlow +
Sargent +
tanniferous +  and furrowed +
reddish-brown +
exfoliating +
cuneate +  and rounded +
Betula alaskana +
2 (?) +  and 3 (?) +
slender +
staminate +  and pistillate +
solitary +  and in small racemose clusters +
ovoid +  and cylindric +
expanding +
Resin birch +  and paper birch +
multibracteate +
Alta. +, B.C. +, Man. +, N.W.T. +, Ont. +, Sask. +, Yukon +  and Alaska. +
100–1200 m +
pistillate +  and staminate +
expanding +
conspicuous +
Rocky or peaty slopes, bog margins, sandhills, open woods +
2 cm20 mm <br />0.02 m <br /> (4 cm40 mm <br />0.04 m <br />) +
1 cm10 mm <br />0.01 m <br /> (4 cm40 mm <br />0.04 m <br />) +
0.8 cm8 mm <br />0.008 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
membranaceous +
10 cm100 mm <br />0.1 m <br /> (14 cm140 mm <br />0.14 m <br />) +
3 cm30 mm <br />0.03 m <br /> (8 cm80 mm <br />0.08 m <br />) +
2 cm20 mm <br />0.02 m <br /> (6 cm60 mm <br />0.06 m <br />) +
distal +  and middle +
not obvious +  and defined +
membranaceous +
Flowering late spring. +
2(-3)-carpellate +
J. Arnold Arbor. +
1-seeded +  and 2-winged +
extended +
crowded +  and imbricate +
deciduous +
(1-)3-lobed +
expanding +
not woody +  and leathery +
2 (?) +  and 3 (?) +
nearly +  and distinct +
pubescent;abaxially glabrous;sparsely pubescent +
Betula papyrifera subsp. humilis +, Betula papyrifera var. humilis +, Betula papyrifera var. neoalaskana +  and Betula resinifera +
Betula neoalaskana +
species +
excurrent +  and branching +
differentiated +
broader +
tanniferous +
light +, nearly white +  and reddish-brown +
soft +  and hard +