Flora of the Canadian Arctic Archipelago
English: Dwarf birch, ground birch, resin birch,
French: Bouleau glanduleux,
Inuktitut: Napaaqturalaat (little trees), avaalaqiat (avalaqiat), kakivaiti.
Betulaceae, Birch family.
Published in Fl. Bor.-Amer. 2: 180.1803.
Type: Described from Canada: James Bay.
Vegetative morphology. Plants 10–30(–50) cm high (on Arctic islands); shrubs; forming colonies by layering; glandular viscid (large glands). Aerial stems erect, or prostrate. Branches red-brown, or brownish (differentiated into short and long shoots; lenticels pale); covered with numerous, raised, large resinous wart-like glands (these usually large and transparent or whitish); glabrous, or glabrescent. Branchlets red-brown; glabrous (at the tips of twigs). Leaves distributed along the stems; alternate (2-ranked); dying annually and non-persistent (deciduous). Petioles 2–6(–10) mm long; hairy (with minute hairs). Juvenile leaves glabrous. Leaf blade bases obtuse, or rounded. Blades 5–20 mm long (-40 mm long further south), 3.5–15(–40) mm wide (further south; see image library), ovate or obovate (to orbiculate, or round), flat, veins pinnate (with 2–6 pairs of lateral veins). Blade adaxial surface fresh green (dark) or shiny, glabrous. Blade abaxial surface glabrous or hairy (especially along the major veins and in vein axils, often covered with resinous glands). Blades 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; apices obtuse, or rounded.
Reproductive morphology. Plants monoecious. Flowering stems with leaves (on short shoots). Inflorescences catkins; dense; cylindrical (erect); 7–12 cm long (2.2.5–5 mm wide in flower); not elongating as the fruit matures (shrinking in length but becoming wider). Pedicels present. Catkins flowering as leaves emerge. Female catkins (5–)10–15(–25) mm long; 3–12 mm wide; stout; borne on a flowering branchlet (1–2 mm long). Floral bracts green (or a calyx in the male flowers); 15–20 mm long; 8–16 mm wide (in fruit); apices divided into 3-lobes. Flowers unisexual. Staminate flowers inconspicuous (staminate catkins mostly terminal on branchlets, rarely present on herbarium specimens). Sepals absent (female flowers), or conventional (male flowers). Petals absent. Stamens present (male flowers), or absent (female flowers); (1–)2–3(–4). Ovary inferior; carpels 2; syncarpous. Styles 2; free (or nearly free). Ovules per ovary 1. Fruit sessile; stalk 1.5–4 mm long; dry; a samara (with wings narrower than the body, broadest near the tip and extended slightly beyond the body). Seeds 1.
Chromosome information. 2n = 28.
2n (4x) = 28. Poucques (1949c); Jørgensen et al. (1958, Greenland); Packer (1964, northwestern Canada); Dugle (1966); Löve and Löve (1966b, northeastern USA; 1982, central Canada); Dawe and Murray, in Löve (1979, Alaska); Sulkinoja (1990, Greenland).
Ploidy levels recorded 4x.
Indigenous knowledge. Inuktutuk names are napaaqturalaat (little trees) and avaalaqiat (avalaqiat). 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, and they were used for making fishing spears, Kakivaiti (Taamusi Qumaq 1988).
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 the boughs fresh for a longer period of time.
Dwarf birch was a useful plant when Inuit were still living mainly on the land. It was their bedding of choice because it did not flatten under a sleeping person. Sometimes because avaalaqiat was not available everywhere, women would collect the straight long twigs and tie them together with sinew. They would produce a wonderful bedding mat that could be rolled up easily and simply rolled out. This mat would be taken with them if they needed to move to a new home. Birch was also used as firewood and was a nice flavouring when drying meat. It was easy to make a broom out of birch twigs; pegs were also made to keep the edges of drying skins stretched (Kalluak, Mark, personal communication, reported in Mallory and Aiken 2004).
Ecology and habitat. Substrates: tundra; rocks, gravel; with high organic content, peat; acidic.
North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago limited (but locally abundant). Low Arctic. Arctic islands: Baffin, Banks, Victoria, Southampton.
Northern hemisphere distribution. North American. West Alaska, North Alaska Yukon, Central Canada, Labrador Hudson Bay, West Greenland.
General 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. In parts of Alaska and near Churchill, Manitoba, where the ranges of these species overlap, B. glandulosa integrates with B. nana, forming a confusing complex of intermediate forms with plants intermediate between B. glandulosa and B. nana subsp. exilis. Whenever they remain in isolation, the species remain reasonably distinct and easy to identify. In southern Greenland, B. glandulosa hybridises with B. nana and with B. pubescens.
Jacobs et al. (1985) described pollen deposition and the distribution of Betula glandulosa at the limit of Low Arctic tundra in southern Baffin Island.
Illustrations. • Habitat: Churchill. Plants in the foreground forming a thicket in low lying swampy land. Manitoba, Churchill. Aiken and Brysting 01–012. CAN. • Habitat: Baffin Island. Shrubs to the left of the marker growing on a grassy hillside towards the northern limits of distribution. Baffin Island, Meta Incognita Peninsula, Soper River Valley, near Mt. Joy. Aiken and Iles 2002. No voucher. • Flowering branch with male and female catkins. Branch with deep red female catkins and yellowish male catkins. Nunavut, Baffin Island, Iqaluit. 5 July, 2004. Aiken and LeBlanc 04–002. CAN 586474. • Close-up of male and female catkins. a, female catkin with two stigmas per flower exposed; b, male catkin with young red anthers exposed. Aiken and LeBlanc 04–002. CAN 586474. • 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 hybridisation may be involved. Aiken and Brysting 01–012. CAN. • Close-up of branch. Fruiting female catkins. Branch has conspicuous warty resinous glands. Arrow at A points to gland with resinous drop; arrow at B 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. Note the green bracts are equal in length and have a hairy fringe. Nunavut, Baffin Island, Soper River. July, 2002. Aiken. No voucher. • Old male catkin. Male 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 in fruit. Red stigmas on the catkin. Note presence of the inferior ovary that contains a single seed and two red stigmas on each fruit. Nunavut, Rankin Inlet. Aiken and Brysting 01–053. CAN. • Close-up of old male catkin. Scales of the catkins are deep reddish and anthers that have shed pollen are pale orange. Note presence of warty resinous glands on the stem. • 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. These were stems collected over a distance of about 1 m, growing in mature birch and willow tundra. N.W.T., Tuktoyaktuk. 6 August, 2001. Aiken and Anne Brysting 01–477. CAN. • Leaf colour in the fall. Leaves turning reddish orange in the fall. Nunavut, Baffin Island, Tarr Inlet hill. 20 August, 2006. Aiken. No voucher. • Plant dying in the centre. Plant that has died off in the centre and is showing the straight branches used for weaving mats. Nunavut, Baffin Island, Tarr Inlet. 20 August, 2006. Aiken. No voucher. • Mat of woven branches. Mat of birch branches woven together, showing a traditional use of this plant. Property of Bert and Joanne Rose. Nunavut, Baffin Island, Iqaluit. October, 2006. Bert Rose. • Close-up of mat. Close-up of the mat showing leaves still attached to some of the twigs. Mat of birch branches woven together, showing a traditional use of this plant. Property of Bert and Joanne Rose. Nunavut, Baffin Island, Iqaluit. October, 2006. Bert Rose. • Arctic Island Distribution.
This publication is available on the internet (posted May 2011) and on CD-ROM (published in 2007). These versions are identical in content, except that the errata page for CD-ROM is accessible on the main index page of the web version.
Recommended citation for the web-based version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada, Ottawa. http://nature.ca/aaflora/data, accessed on DATE.
Recommended citation for the CD-ROM version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. [CD-ROM] NRC Research Press, National Research Council of Canada, Ottawa..