Salicaceae of the Canadian Arctic Archipelago

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


Salix arctica Pall.

Arctic willow.

Fl. Ross. 1: 86. 1788.

Salix anglorum auct. non Cham.

Salix anglorum var. antiplasta Schneid.

Salix anglorum var. araioclada Schneid.

Salix anglorum var. kophophylla Schneid.

Salix arctica subsp. crassijulis (Trautv.) Skvort.

Salix arctica subsp. tortulosa (Trautv.) Hultén

Salix arctica var. antiplasta (Schneid.) Fern.

Salix arctica var. araioclada (Schneid.) Raup

Salix arctica var. brownei Anderss.

Salix arctica var. kophophylla (Schneid.) Polunin

Salix arctica var. pallasii (Anderss.) Kurtz

Salix arctica var. tortulosa (Trautv.) Raup

Salix brownei (Anderss.) Bebb

Salix crassijulis Trautv.

Salix hudsonensis Schneid.

Salix pallasii Anderss.

Salix pallasii var. crassijulis (Trautv.) Anderss.

Salix tortulosa Trautv.

Plants dwarf shrubs; less than 15 cm high, or more than 15 cm high; 3–25 cm high; not colonial, or forming colonies by layering. Stems. Aerial stems decumbent, or prostrate, or erect. Branches yellow-brown, or yellowish, or gray-brown, or red-brown, or brownish; not glaucous, or thickly glaucous; glabrous, or glabrescent; epidermis not flaky. Branchlets yellow-brown, or red-brown, or violet; not glaucous, or thinly glaucous, or thickly glaucous; glabrous, or hairy; pilose, or villous; hairs sparse, or very dense; hairs spreading. Bud scale inner membrane free but not separating from outer membrane. Stipules. Stipules absent, or present (caducous); leaf-like, or scale-like; apex acute. Petioles. Petioles 2–35 mm long; glandular dots at the base of the leaf absent; deeply concave in cross-section, but margins not covering the groove; glabrous. Petioles adaxial surface puberulent. Leaves. Juvenile leaves yellowish green; glabrous, or hairy; abaxial surface villous (long, straight hairs pointing toward tip); hair sparse; hair white. Blades 1–8.5 cm long; 5.5–60 mm wide; length-width ratio 1–3.6; herbaceous, or leathery; elliptic (narrowly elliptic to subcircular), or circular, or oblanceolate, or obovate (to broadly obovate); revolute, or flat; secondary veins protruding on adaxial and abaxial surfaces, or flat on adaxial surface, protruding on abaxial surface; secondary veins arising along midrib; stomata only on abaxial surface, or stomata on adaxial surface only present along veins or at apex. Blades adaxial surface shiny, or dull; glabrous, or hairy, or glabrescent; hairs pilose (hairs near margin); hairs sparse; hairs white and translucent. Blades abaxial surface glabrous, or hairy, or glabrescent (beard at tip); glaucous; hairs long-silky, pilose; hairs sparse; hairs white, or translucent; hairs spreading, or appressed; hairs straight (typical), or wavy. Leaf bases cuneate, or attenuate, or acute. Leaf margins glandular-dotted and entire; with teeth per cm 1–3; with submarginal glands, or with marginal glands. Leaf margins with glandular hairs toward base only. Leaf apices obtuse, or rounded, or acute.

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; 11–50 mm long; 5–18 mm wide; slender, or stout, or subglobose; peduncles 2–13 mm long; borne on a flowering branchlet; flowering branchlets 2–20 mm long. Female catkins. Female catkins densely flowered, or moderately densely flowered; 11–120 mm long; 8–18 mm wide; slender, or stout, or subglobose; peduncles 4–30 mm long; borne on a flowering branchlet; flowering branchlets 2–80 mm long. Floral bracts. Floral bracts brown, or black (rarely light brown); widest at base, or widest at middle; 1.6–3.7 mm long; hairy all over; hairs sparse; hairs straight (long); entire, or minute undulations (or with 2–3 undulations). Stamens 2; filaments glabrous. Anthers purple (rarely becoming yellowish); ellipsoid; axis straight; 0.4–0.9 mm long. Male flowers. Male flowers abaxial nectaries absent, or one; adaxial nectaries one; adaxial nectaries slender-rod, or broad-rod, or square; adaxial nectaries 0.5–1.2 mm long. Female flowers. Female flowers adaxial nectaries absent; unlobed; broad-rod, or ovate, or slender-rod; 0.4–1.8 mm long; longer than stipes, or equal to stipes (usually 1.5–4X, rarely equal). Stipes 0.2–1.6 mm long. Ovaries inverse club-shaped, or pear-shaped; ovary abruptly tapering to style, or slightly bulged at the base of the style, or gradually tapering to style; hairy; ovary villous. Ovary hair dense, or sparse, or moderately dense; white, or translucent; spreading; wavy; flattened (sometimes refractive). Styles 0.6–2.2 mm long. Stigmas slender-cylindrical (sometimes stout); lobes 0.36–0.56–0.88 mm long. Ovules 10–18. Fruit. Fruit 4–9 mm long; hairy, or glabrescent (sometimes glabrescent).

Chromosome inforamtion. 2n = 76 and 114. 4x Dawson (pers. comm. 1986); Holmen 1952; Mosquin & Haley 1966; Johnson & Packer 1968. 6x Suda & Argus 1969. Russia 4x Zhukova & Petrovsky 1980. 6x Zhukova et al 1973; Petrovsky & Zhukova 1983; Zhukova & Petrovsky 1987. Ploidy levels recorded 4 & 6x.

Distribution. Northern hemisphere: Greenland, Canada, United States, Eurasia. Canada: Alta., B.C., Lab., Man., Nfld., Ont., Que., Yukon, N.W.T., Nunavut. USA: Alaska, Idaho., Mont., Oreg., Wash.

Ecology and habitat. A ubiquitous dwarf shrub often forming prostrate mats spreading from a central stem. It may occur on sparsely vegetated surfaces or spreading over dense tundra vegetation. It grows in most arctic habitats including hummocks in wet sphagnum bogs and sedge meadows, polygonal tundra, solifluction slopes, snow beds, margins of pools, beach ridges, shaley and gypsum ridges, gneissic cliffs, colluvial slopes, talus slopes, imperfectly drained calcareous silty till, muddy salt flats, frost-heaved clay polygons, dry calcareous gravel, and coarse sandy soil. Plants are often heavily browsed by muskox and arctic hares. Elevation 0–700 m.

Notes. Salix arctica is a dwarf shrub, sometimes with long trailing branches that root where they touch the surface. Leaf size and shape are highly variable but the abaxially surface of the leaves is always glaucous and usually clothed with long, straight, appressed hairs that may persist as a ‘beard’ at the tip, the margins are entire. Floral bracts are dark brown and clothed with long, straight hairs.

This circumpolar species is morphologically polymorphic and nomenclaturally confused. Many botanists studying the flora of the Arctic Archipelago have collected what they thought were two or three species of Salix to find on their return that they were all S. arctica. Some taxonomists (Hultén 1967, 1971) have recognized three subspecies in S. arctica. (1) subsp. arctica (circumpolar from Iceland and the Faeroe Islands across northern Russia, Alaska and Canada to Greenland, south to the Hudson Bay shores of Ontario and the Gaspé Peninsula.), (2) subsp. crassijulis (a North Pacific race ranging from Kamchatka and the Russian Far East to the Aleutian Islands, south central and Southeastern Alaska along the coast to northern Washington), and (3) subsp. torulosa (ranging from the mountains of Central Asia to Kamtchatka and the Bering Straits, the Brooks Range and the Rocky Mountains in Alaska, south in the cordillera to southern British Columbia and Alberta). While the phytogeographic pattern of these three races is appealing they are actually very difficult or impossible to separate morphologically. Argus (1973) presented evidence that the latter two subspecies were environmental modifications of one species. He reported that robust plants in the Glacier Bay area of Southeastern Alaska (S. arctica subsp. crassijulis) were associated with nitrogen-rich Alnus thickets whereas small plants (S. arctica subsp. torulosa) from the same area were growing on open moraine. Others have also reported environmental modification of S. arctica. Saville (1964) noted that depauperate specimens occurred in depressions behind beach ridges where they may be immersed in years of high water. Soper & Powell (1985) observed that this species varied considerably according to ecological and edaphic conditions. Dawson (1987) showed that the female-biased sex ratios in S. arctica is environmentally controlled (female plants are significantly over-represented in mesic-wet, more fertile, low soil temperature sites, whereas, male plants are predominant in drier, less fertile sites). In light of this evidence the possibility that the complex morphological variability within S. arctica may be ecophenic or ecotypic deserves study. Other characters cited to separate subsp. torulosa (Hultén 1971) including leaf shape and floral bract colour do not withstand scrutiny (Argus 1973, Raup 1959). The morphological variability within S. arctica, although striking, does not seem to reflect taxonomic differences.

Age of Salix arctica: about 130 years, Franz Joseph Fjord, East Greenland (Gelting 1934); in the Mesters Vig area of East Greenland (King Oscars Fjord) Raup (1965) reported that most specimens were about 60 years old with one reaching 180 and another 236 years; the oldest Canadian material is 85 years from Lake Hazen, Ellesmere Island (Savile 1979).

In northern Greenland Salix arctica is one of the primary foods for muskox, arctic hare, and collared lemming (Klein & Bay 1991).

Hybrids

Salix arctica × arctophila (Polunin 1940). There are a number of putative hybrids in Canadian Museum of Nature from Baffin and Ellesmere islands. These plants have leaves and branchlets almost glabrous as in S. arctophila, but bearing only a few long hairs, and ovaries with flattened, refractive hairs as in S. arctica, not ribbon-like as in S. arctophila. On Bylot Island, Drury (1962: 88–89) reported collecting material that resembled S. arctophila but which intergraded with S. arctica. These specimens need to be restudied.

Representative specimens: Soper, J.D. 122106, Baffin Island, Panguirtung Fjord. 26 July 1924. CAN 46583; Wynne-Edwards, V.C. Baffin Island, Head of Clyde Inlet. 11 July 1950. CAN 283881; Polunin, N. 2376. Baffin Island, Cape Dorset. 15 June 1924. CAN 46516; Soper, J.D. 132178. Baffin Island, Head of Kinga Fjord. 31 July 1924. CAN 46520; Malte, M.O. s.n. Ellesmere Island, Craig Harbour. 2 Aug. 1927. CAN 46377; Malte, M.O. 118599. Ellesmere Island, Dundas Harbour. 27 July 1927. CAN 46381.

Salix arctica × S. glauca (Argus 1965, 1973, Bay 1992). In 1965 Argus wrote, ‘This hybrid is characterized by various combinations of the characteristics of S. arctica and S. glauca. The S. glauca characteristics include erect habit, leaves less oblanceolate and without the attenuate base of S. arctica, shorter petioles, bracts light-colored with shorter wavy trichomes [hairs], and a divided style. The S. arctica characteristics include prostrate habit, pruinose [glaucous] stems and buds, sparse branchlet-pubescence, dark-colored bracts with long, straight trichomes, leaves with long straight trichomes on the lower [abaxial] surface projecting in a ‘beard’ at the apex, capsules reddish with long stigmas, and dark colored anthers.’ Specimens identified as hybrids combine these characters in various ways. On Baffin Island the hybrid is difficult to recognize because there S. glauca and S. arctica so converge in their morphology that the recognition of intermediates is difficult.

Illustrations. • Habit. Salix arctica: plant growing on stony gravel. Photograph taken at Iqaluit, Baffin Island, Nunavut by Jack Gillett 22 July 1982. Voucher specimen: Jack Gillett 18992, CAN. • Habit. Salix arctica: plant forming a prostrate mat on a lakeshore. Photograph taken at Lake Hazen, Ellesmere Island, Nunavut, by Lynn Gillespie, 11 Aug. 1995. • Habit. Salix arctica: plant forming a prostrate mat on a glacial moraine. Photograph taken at Glacier Bay, Alaska, 29 June 1967. • Habit. Salix arctica: plant growing in rocks. Capsules have opened releasing seeds surrounded by hairs (fluff). Photograph taken at Alexandra Fiord, Ellesmere Island, Nunavut, by Lynn Gillespie, 30 July 1991. • Habitat. Salix arctica: habitat. Photo taken at Cambridge Bay, Victoria Island, Nunavut, by Laurie Consaul. Voucher specimen: Laurie Consaul and Lynn Gillespie 1137, CAN. • Close-up of plant. Salix arctica: Photo taken in the N.W.T. Susan Aiken 97–021. • Close-up of female flowering plant. Salix arctica: close-up of female flowering plant. Photo taken at Iqaluit, Baffin Island, Nunavut by Susan Aiken, 30 Aug. 1997, Voucher specimen: Susan Aiken and Cheryl McJannet, 97021, CAN. • Close-up of plant. Salix arctica: close-up of plant with broadly elliptic leaves. The ovaries vary in colour from yellow (shown here) to red or even green. Photograph taken at Glacier Bay, Alaska, 29 June 1967. • Close-up of plant. Salix arctica: close-up of the plant with oblanceolate leaves. Photograph taken at Glacier Bay, Alaska, 29 June 1967. • Close-up of male catkin. Salix arctica: close-up of a male catkin. Catkins are densely flowered, the leaves on the flowering branchlet show the long "beard" of hairs at the tip. Photograph taken at Sachs Harbour, Banks Island, N.W.T. by Jack Gillett, 22 July 1982. Voucher specimen: Jack Gillett, 18865, CAN. • Female catkins. Salix arctica: Female catkins are erect and densely flowered. Photo taken by Donald Gunn; slide number: S84–5377, Photo Library, Canadian Museum of Nature. • Close-up of female catkin. Salix arctica: Female catkin with red styles and stigmas, densely hairy ovaries, and floral bracts with long, straight hairs. Photograph taken by Donald Gunn; slide number: S84–5379, Photo Library, Canadian Museum of Nature. • Close-up of female catkin. Salix arctica: Female catkins are densely flowered, the leaves on the flowering branchlet show the long "beard" of hairs at the tip. Photograph taken at Iqaluit, Baffin Island, Nunavut, by Jack Gillett, 22 July 1982. Voucher specimen: Jack Gillett, 18992, CAN. • Line drawing. Salix arctica: A. Male catkins are borne on short, leafy flowering branchlets. B. Male flowers have 2 stamens, a floral bract with long straight hairs, and a single nectary. C. A female catkin borne on a short, leafy flowering branchlet. The vegetative shoot bears elliptic to broadly elliptic leaves. D. Female flowers have villous ovaries, a long style, a long-hairy floral bract, and a single floral nectary that is longer than the stipe. • Arctic Island Distribution.


Cite this publication as: G.W. Argus, C.L. McJannet and M.J. Dallwitz (1999 onwards). ‘Salicaceae of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval.’ Version: 2nd November 2000. http://http://www.mun.ca/biology/delta/arcticf/. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).

Index