Betula glandulosa Michx.
Dwarf birch, ground birch, resin birch, bouleau glanduleux.
Betulaceae, birch family.
Fl. Bor.-Amer.2:180.1803.
Vegetative morphology. Plants shrubs; 10–30(–50) cm high (on Arctic Islands); woody shrubs with matted prostrate or ascending stems with warty resinous glands. Aerial stems erect, or prostrate; covered with numerous, raised, large resinous wart-like glands (these usually large and transparent or whitish); glabrous (but not smooth). Branches red-brown, or brownish (differentiated into short and long shoots; lenticels pale); glabrous, or glabrescent. Branchlets red-brown; glabrous (at the tips of twigs). Leaves distributed along the stems; alternate (2-ranked); existing for a single season or less (deciduous). Petioles 2–6(–10) mm long; hairy (with minute hairs). Leaf blade bases obtuse, or rounded. Juvenile leaves glabrous. Blades 5–20(–40) mm long (further south); 3.5–15(–40) mm wide (further south, see image library). Blades ovate, or obovate (to orbiculate, or round); flat; veins pinnate (with 2–6 pairs of lateral veins). Blades secondary veins arising along midrib. Blades adaxial surface glabrous. Blades abaxial surface glabrous, or hairy (especially along the major veins and in vein axils, often covered with resinous glands). Blade margins not lobed (considered deeply crenate). Blade margins crenate, or dentate (teeth obtuse to rounded); with teeth toward the apex; with teeth per cm 2–8. Leaf apices obtuse, or rounded.
Reproductive morphology. Plants monoecious. Flowering stems present. Flowering stems with leaves (on short shoots). Inflorescence a catkin; dense; cylindrical (erect). Pedicels absent. Catkins flowering with the opening of leaf buds. Female catkins densely flowered; (5–)10–15(–25) mm long; 3–12 mm wide; stout; peduncles 1–2 mm long; borne on a flowering branchlet. Staminate flowers inconspicuous (staminate catkins mostly terminal on branchlets, rarely present on herbarium specimens). Floral bracts green (lobes about equal in length); widest toward tip; 1.5–2 mm long; 0.8–1.6 mm wide; apex obtuse. Perianth absent. Flowers unisexual. Gynoecia inferior. Carpels syncarpous; 2. Styles 2; free (or nearly free). Ovules 1. Fruit dry; a samara (with wings narrower than the body, broadest near the tip and extended slightly beyond the body). Fruit information not found. Seeds 1.
Chromosome information. 2n = 28. 4x Poucques (1949c); Jørgensen et al. (1958 Greenland); Packer (1964 northwestern Canada); Dugle (1966); Löve and Löve (1966b north eastern USA, 1982 central Canada); Dawe and Murray (1979 Alaska); Sulkinoja (1990 Greenland). Ploidy levels recorded 4x.
Distribution. Northern hemisphere distribution: Greenland, Canada. Yukon, Northwest Territories Islands, Continental Northwest Territories, Nunavut Islands, Continental Nunavut, Northern Québec. Low arctic. Range in the Canadian Arctic Archipelago limited (but locally abundant). Arctic Islands: Baffin, Banks, Victoria, Southampton.
Ecology and habitat. Substrates: tundra; acidic; rocks, gravel; with high organic content, or peat.
Indigenous knowledge. Inuktutuk names: avalaqiat,
napaaqturalaat (little trees). According to Naujamiut, the Inuit from
Upernavik, in West Greenland, the word avaalaqiat is related to
avaaq "back of the head’ (Paillet, 1973). They are used for cooking
and for bedding in the Kivalliq area and in Nunavik (Taamusi Qumaq 1988). They
were used for making fishing spears, Kakivaiti. They are found on dry
tundra and steep-banked shorelines. In the central Canadian Arctic the dwarf
birch was probably used by the Inuit, only for firewood. Ptarmigan feed on the
buds and catkins, and small passerine birds feed avidly on insects visiting the
blooming catkins. (Burt,2000). The unfolded birch leaves are sticky on the
underside and children (of the Bathurst Inlet area at least), stick them to
their ears and make "earrings" of them (Burt, 2000).
Andre and Fehr (2000)
reported that Gwich'in people use this plant for flooring in tents and that when
placed among spruce boughs the birch keeps sthe boughs fresh longer.
Notes. Furlow (1997) stated that B. glandulosa is the characteristic dwarf birch of upland habitats throughout the west occurring as well in dry open areas across the north. Where their ranges meet B. glandulosa integrates with B. nana forming a confusing complex of intermediate forms. Plants intermediate between B. glandulosa and B. nana subsp. exilis make up a continuum of forms linking the typical forms of Betula nana and B. glandulosa in parts of Alaska where the ranges of these species overlap. Whenever they remain in isolation, the species remain reasonably distinct and easy to identify. In southern Greenland, B. glandulosa hybridizes with B. nana and with B. pubescens.
Illustrations. • Plant habitat: Churchill. Plants in the foreground forming a thicket in low lying swampy land. Churchill, Manitoba. Aiken and Brysting 01–012. CAN. • Plant habitat: Baffin. Shrubs to the left of the marker growing on a grassy hillside towards the northern limits of distributuion. Baffin Island, Mega Incognita Peninsula, Soper River Valley, near Mt. Joy. Aiken and Ilses, 2002. No voucher. • Close-up of branch. Branch with catkins. Specimens from Churchill, Manitoba, have less conspicuous warty resinous glands on the branches than plants in other parts of the distribution range. There is the suggestion that some hybridization may be involved. Aiken and Brysting 01–012. CAN. • Close-up of branch. Branch with catkins setting seeds. Specimens from Nunavut, Rankin Inlet. Note conspicuous warty resinous glands on the branch. White arrow points to gland with resinous drop; blue arrow indicates dried gland. Aiken and Brysting 01–053 CAN. • Close-up of anthers.. Portion of a catkin with hairy scales that subtend the flowers and bi-lobed, pre-anthesis anthers. Nunavut, Baffin Island, Soper River. July, 2002. Aiken. No voucher. • Old catkin. Catkin from which the anthers have been shed and the scales subtending the flowers have turned or are turning brown. Nunavut, Baffin Island, Soper River. July, 2002. • Close-up of catkin. red stigmas. Nunavut, Rankin Inlet. Aiken and Brysting 01–053 CAN. • Close-up of old catkin. • Close-up of leaves. Two branches from re-growth of shrubs that had been cut back to make a path. Note the range in leaf sizes from a few cm in diameter to a few mm, in stems collected over a distance of about 1 m. Growing in mature birch and willow tundra. Northwest Territories, Tuktoyaktuk. Aiken and Anne Brysting 01–477. 6 August 2001.CAN. • Arctic Island Distribution.
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, L.J. Gillespie, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, A.K. Brysting and H. Solstad. 1999 onwards. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).
