Salicaceae of the Canadian Arctic Archipelago

G.W. Argus, C.L. McJannet, and M.J. Dallwitz

Salix uva-ursi Pursh

Bearberry willow.

Fl. Amer. Sept. 2: 610. 1814.

Salix arbuscula var. labradorica (Anderss.) Anderss.

Salix cutleri Tuckerman

Salix cutleri var. labradorica (Anderss.) Anderss.

Salix ivigtutiana Lundstr.

Salix myrsinites var. parvifolia Lange

Plants dwarf shrubs; less than 15 cm high; 1–5 cm high; forming colonies by layering. Stems. Aerial stems prostrate. Branches red-brown, or gray-brown, or yellow-brown; not glaucous; glabrous; epidermis not flaky, or flaky. Branchlets yellow-green, or yellow-brown; not glaucous; glabrous; puberulent; hairs sparse; hairs appressed, or fishhook-curved. Bud scale inner membrane fused to outer layer. Stipules. Stipules present, or absent; leaf-like, or scale-like; apex acute. Petioles. Petioles 2–6.5 mm long; glandular dots at the base of the leaf absent; shallowly concave in cross-section, or deeply concave in cross-section, but margins not covering the groove; glabrous. Leaves. Juvenile leaves yellowish green; glabrous, or hairy; abaxial surface pilose, or puberulent; hair sparse; hair white. Blades 0.8–2.3 cm long; 3.5–10 mm wide; length-width ratio 1.7–3.6; herbaceous, or leathery; obovate (to broadly obovate), or oblanceolate, or elliptic; flat; secondary veins protruding on adaxial and abaxial surfaces; secondary veins arising along midrib; stomata on both adaxial and abaxial surfaces, or stomata on adaxial surface only present along veins or at apex, or stomata only on abaxial surface. Blades adaxial surface shiny, or highly glossy; glabrous, or hairy; hairs puberulent, or long-silky; hairs sparse; hairs white and translucent. Blades abaxial surface glabrous; glaucous. Leaf bases cuneate, or obtuse, or acute. Leaf margins entire and serrulate, or crenate, or glandular-dotted, or entire; with teeth toward apex only, or all around leaf; with teeth per cm 4–10; with marginal glands. Leaf margins with glandular hairs toward apex only, or all around leaf. Leaf apices retuse, or acute, or rounded.

Plants dioecious. Catkins. Catkins flowering with the opening of leaf buds; one to several catkins just below tip of previous year’s shoot. Male catkins. Male catkins densely flowered; 6–17 mm long; 5–8 mm wide; stout, or subglobose; peduncles 1–6 mm long; borne on a flowering branchlet; flowering branchlets 0.5–9 mm long. Female catkins. Female catkins densely flowered; 8–39 mm long; 6–10 mm wide; slender, or stout, or subglobose; peduncles 1.5–10 mm long; borne on a flowering branchlet; flowering branchlets 2–10 mm long. Floral bracts. Floral bracts brown, or black, or tawny, or light rose; widest at middle, or widest toward tip; 1.1–1.8 mm long; hairy all over, or glabrous; hairs sparse; hairs straight, or wavy; entire. Stamens 1 (rarely two); filaments glabrous. Anthers purple becoming yellow, or reddish becoming yellow; ellipsoid, or stout-cylindrical; axis straight, or axis twisted; 0.4–0.7 mm long. Male flowers. Male flowers abaxial nectaries absent; adaxial nectaries one; adaxial nectaries slender-rod, or broad-rod; adaxial nectaries 0.6–0.9 mm long. Female flowers. Female flowers adaxial nectaries absent; unlobed; slender-rod, or broad-rod; 0.5–0.8 mm long; shorter than stipes, or longer than stipes. Stipes 0.32–1.6 mm long. Ovaries ovate, or pear-shaped; ovary gradually tapering to style; glabrous. Styles 0.48–1 mm long. Stigmas slender-cylindrical, or broad-cylindrical; lobes 0.1–0.23–0.4 mm long. Ovules 6–10. Fruit. Fruit 3–5 mm long; glabrous.

Chromosome inforamtion. 2n = 38. Jorgensen, Sorensen, & Westergaard 1958, Löve & Löve 1966. Ploidy levels recorded 2x.

Distribution. Northern hemisphere: Greenland, St. Pierre and Miquelon, Canada, United States. Canada: Lab., N.B., Nfld., N.W.T. (Frank.) (old), N.S., Que., Nunavut. USA: Maine, N.H., N.York, Vt.

Ecology and habitat. A dwarf shrub forming mats on exposed, often dry or moist, calcareous and granitic rocks, boulders, gravel, and sand on beaches, outcrops, and snow beds.

Notes. Salix uva-ursi is a dwarf shrub that form large mats by with prostrate branches; its leaves are entire and elliptic; and ovaries are glabrous.

Hybrids

Salix ×´peasei Fern. (S. herbacea × uva-ursi). This hybrid combines that characters of the parental species. It is coarser than S. herbacea and has thick, trailing stems. Its leaves are crenate as in S. herbacea but its longer catkins resemble S. uva-ursi. Polunin (1940) reports it from Chesterfield Inlet and includes it in the key and illustrates in his Circumpolar Arctic Flora (Polunin 1959). This hybrid was described based on material from Mt. Washington, New Hampshire.

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Illustrations. • Habit. Salix uva-ursi: habit. Photograph taken at Clearwater Lake, Quebec, 16 July 1983. • Habit. Salix uva-ursi: habit. When the plant is growing over warm rocks the shoots become longer and bear larger leaves. Photo taken at Iqaluit, Baffin Island, Nunavut, Aug. 1997. Voucher specimen: Susan Aiken and Cheryl McJannet 97011, CAN. • Close-up of leaves and overwintering buds. Salix uva-ursi: close-up of leaves and overwintering buds from the previous picture. Photo taken at Iqaluit, Baffin Island, Nunavut, by Susan Aiken, Aug. 1997. Voucher specimen: Susan Aiken and Cheryl McJannet 97011, CAN. • Habit. Salix uva-ursi: habit, scale bar in cm. Turning orange-brown in the fall. Photo taken at Iqaluit, Baffin Island, Nunavut, Aug. 1997. Voucher specimen: Susan Aiken and Cheryl McJannet 97045, CAN. • Habitat. Salix uva-ursi: mat growing in rocky lichen tundra. Photograph taken at Clearwater lake, Quebec, 16 July 1983. • Female plant. Salix uva-ursi: prostrate mat with short, erect catkins. The ovaries typically are reddish and glabrous. The leaves are small and elliptic. Photo taken by Donald Gunn; slide number: S84–5381, Photo Library, Canadian Museum of Nature. • Close-up of a female catkin. Salix uva-ursi: a female catkin with glabrous, reddish ovaries. Photograph taken at Iqaluit, Baffin Island, Nunavut, by Jack Gillett, 22 July 1982. Voucher specimen: Jack Gillet 18992, CAN. • Arctic Island Distribution.