Flora of the Canadian Arctic Archipelago
English: Richardson's willow,
French: Saule de Richardson,
Salicaceae, Willow family.
Published in Fl. Bor.-Amer. 2: 147. 1838
Type: Canada: N.W.T., Ft. Franklin, Mackenzie River. Holotype: GH [n.v.]
Synonymy. Salix lanata L. subsp. richardsonii (Hook.) A. K. Skvortsov, in Tolm. (1966b), Fl Arct. URSS 5: 103. 1966.
Salix richardsonii Hook. var. mckeandii Polunin, Bull. Natl. Mus. Canada 94 (Biol. Ser. 24): 167. 1940.
Vegetative morphology. Plants 30–650 cm high; shrubs; low shrubs, or mid shrubs, or tall shrubs; not colonial. Aerial stems erect. Branches red-brown, or violet, or yellow-brown; not glaucous, or weakly glaucous, or strongly glaucous; glabrous, or hairy, or glabrescent (patches of hairs); hairs villous. Branchlets red-brown, or yellow-brown; not glaucous; hairy; villous, or pilose. Branchlet hairs sparse, or moderately dense, or very dense; spreading. Buds caprea-type. Leaves present; distributed along the stems; alternate; dying annually and non-persistent, or marcescent. Stipules present; on first leaves foliaceous; on leaves formed later in the season foliaceous; persisting for 2 or more years, or deciduous in autumn; green; apex acuminate, or acute. Petioles 2–27 mm long; convex to flat in cross section, or shallowly concave in cross section; glabrous, or hairy, or glabrescent; villous. Juvenile leaves yellowish green; hairy; abaxial surfaces villous, or pilose (sometimes glabrous); abaxial hairs sparse, or moderately dense; abaxial hairs white (or white and rust-coloured). Leaf blade bases cuneate, or obtuse (slightly decurrent or concave). Blades 23–100 mm long, length-width ratio 1.2–4.2, 7–55 mm wide, elliptic (narrowly to broadly elliptic) or obovate. Blade adaxial surface shiny, glabrous or hairy or glabrescent, hairs villous or pilose, hairs moderately dense or sparse, hairs white, or translucent or a mixture of white and rust-coloured hairs. Blade abaxial surface glaucous, hairy or glabrescent, hairs pilose or villous, hairs sparse, hairs white or a mixture of white and rust-coloured, hairs curved, hairs spreading. Blade margins slightly revolute or flat. Blade margins entire and glandular-dotted or serrulate, with teeth all around the blade (rarely only toward base), with teeth per cm 2–13 (6); apices acuminate, or obtuse.
Reproductive morphology. Plants dioecious. Inflorescences catkins. Pedicels absent. Catkins flowering before leaves emerge. Male catkins 22–53 mm long; 16–20(–24) mm wide; stout, or sub-globose; peduncles 0–7 mm long; sessile. Female catkins 25–69 mm long; 13–20 mm wide; slender, or stout; peduncles 0–9 mm long; borne on a flowering branchlet, or sessile (or borne on a short flowering branchlet); flowering branchlets 0–2 mm long. Floral bracts black, or brown; 2.4–3.2 mm long; hairy all over; hairs moderately dense; hairs straight; apices acute, or rounded, or retuse; apices entire. Flowers unisexual. Sepals absent. Petals absent. Stamens 2; stamen filaments glabrous. Anthers purple becoming yellow; ellipsoid, or short-cylindrical; 0.5–0.8 mm long. Male flowers abaxial nectaries absent. Male flowers adaxial nectaries narrowly oblong, or oblong; 0.73–1.75 mm long. Female flowers abaxial nectaries absent. Female flowers adaxial nectaries narrowly oblong, or oblong, or flask-shaped; 0.6–1.5 mm long (2–3 times longer than the stipe); longer than stipes. Ovary carpels 2. Stipes 0.4–1 mm long. Ovaries pear-shaped; gradually tapering to style; glabrous. Styles 0.96–2.8 mm long. Stigma lobes 0.32–0.63–0.86 mm long. Ovules per ovary 22–37. Fruit a capsule; 4.5–6.8 mm long; glabrous.
Chromosome information. 2n = 38.
2n (2x) = 38. Zhukova (1969, 1980, northeastern Asia); Zhukova and Petrovsky (1972, northeastern Asia); Petrovsky and Zhukova (1983a, 1983b, northeastern Asia).
Ploidy levels recorded 2x.
Ecology and habitat. Forming thickets 0.3–1 m tall on calcareous or sometimes igneous substrates. Growing on sand and gravel terraces, silty river beds, drumlin fields, gravel ridges, cliff ledges, and snowbeds.
North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut. Arctic islands: Baffin, Banks, Victoria, Prince of Wales, Southampton (Boothia Peninsula).
Northern hemisphere distribution. North American (more western), or Siberian. AnabarOlenyok, Kharaulakh, YanaKolyma, West Chukotka, Wrangel Island, South Chukotka, East Chukotka, West Alaska, North Alaska Yukon, Central Canada, Labrador Hudson Bay.
General notes. Salix richardsonii is a shrubby species with persistent, prominent, slender stipules with a long attenuate tip and a broader, inequilateral base. Catkins are sessile or with a few green bracts at the base. The ovaries are glabrous, and the nectaries 2–3 times as long as the stipes. It is similar to S. pulchra, but because the latter species is known in our area only on Banks Island, their separation will not often pose a problem. On Banks Island, the two species are easily separated by the hairiness of their ovaries.
This species is often treated as S. lanata subsp. richardsonii (Argus 1973, Skvortsov 1968). Subspecies rank was proposed by Skvortsov because the two taxa apparently intergrade where their ranges overlap in the Ural Mountains, Russia (Skvortsov 1968, 1999). The intergradation, however, does not seem to extend beyond the overlapping populations. This situation is very similar to that found in S. planifolia - S. pulchra, and S. brachycarpa - S. niphoclada. Trinomial nomenclature, in all of these cases, was used to show the close evolutionary relationship between these taxa. But inasmuch as such nomenclature is cumbersome to use and is therefore often ignored by the non-taxonomist, its information value is minimal. In addition, since the evidence of intergradation is often indistinct, it appears appropriate to use binomial nomenclature. I have decided to treat these taxa as distinct species because the area of overlap between them is relatively small, and because the use of trinomial nomenclature in taxa with widely separated ranges is unnecessarily cumbersome.
Polunin (1940) described S. richardsonii var. mckeandii as differing from the species in having smaller leaves [1–3 (4) cm long and 0.4–1.3 (1.5) cm wide] and capsules borne on short, hairy stipes. The type, which is in the British Museum, and the specimens he cites (1940: 169) require study. It is treated here as a synonym of S. richardsonii.
This species, along with S. alaxensis and S. pulchra, are the tallest willows in the Arctic Archipelago. Plants up to 8 ft tall have been reported from the south coast of Victoria Island (Holm 1922). In the Masik River valley, southwestern Banks Island, it forms a dominant shrub tundra in association with S. alaxensis and S. pulchra (Kuc 1970, 1974).
Salix calcicola × S. richardsonii. Polunin (1940) described S. richardsonii var. mckeandii and S. calcicola var. nicholsiana, which he thought were hybridising and intergrading on Baffin and Southampton islands. I have not seen the types of either of these varieties. There is some suggestion of hybridisation between S. calcicola and S. richardsonii on Southampton Island, but it is not clear, and there is no evidence of hybridisation between these two species elsewhere. This problem requires field study.
Illustrations. • Habitat. Plant a shrub with shiny adaxial leaf surfaces. Nunavut, Victoria Island, Cambridge Bay. July, 1997. Laurie Consaul 1138 and 1139 and Lynn Gillespie. CAN. • Habit. Plant growing in thickets. Note the persistent, prominent slender stipules. Victoria Island, Cambridge Bay. July, 1997. Laurie Consaul 1105 and Lynn Gillespie. CAN. • Female fruiting plant. Female fruiting plant. Capsules have opened releasing seeds surrounded by copious hairs (fluff). Nunavut, Victoria Island, Cambridge Bay. July, 1997. Laurie Consaul 1103 and Lynn Gillespie. CAN. • Female catkin and vegetative shoot. Short vegetative shoot in front of catkin. Nunavut, Victoria Island, Cambridge Bay. July, 1997. Laurie Consaul 1105 and Lynn Gillespie. CAN. • Close-up of female catkin. Female catkins are sessile on the branch. There may be two or three small, green bracts (white arrow) at base. The ovaries are glabrous. Some capsules on the right side of the catkin have opened to release seeds surrounded by hairs (fluff). Victoria Island, Cambridge Bay. July, 1997. Laurie Consaul 1103 and Lynn Gillespie. CAN. • 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..