Flora of the Canadian Arctic Archipelago

DELTA Home

S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, L.J. Gillespie, A.K. Brysting, H. Solstad, and J.G. Harris

Salix niphoclada Rydberg

English: Barren-ground willow.

Salicaceae, Willow family.

Published in Bull. N.Y. Bot. Gard. 1: 272. 1899.

Type: Canada, N.W.T., Mackenzie River north of Arctic Circle. Taylor 60. Holotype: CAN.

Synonymy. Salix fullertonensis C.K. Schneider, Bot. Gaz. 66: 340. 1918.

Salix muriei Hultén, Acta Univ. Lund., n. f., avd. 2, 39, 1: 531. 1943.

Salix brachycarpa Nutt. subsp. niphoclada (Rydberg) Argus, Contr. Gray Herb., Harvard Univ, 196: 119. 1965.

Salix brachycarpa Nutt. var. fullertonensis (C. K. Schneider) Argus, Contr. Gray Herb., Harvard Univ, 196: 125. 1965.

Salix fullertonensis C. K Schneider, Bot. Gaz. 66: 340. 1918.

Salix brachycarpa var. mexiae C. R. Ball, Univ. Calif. Publ. Bot. 17: 412. 1934.

Salix glauca var. niphoclada (Rydberg) Wiggins, in Wiggins and Thomas, Fl. Alaska Arctic Slope. 144. 1962.

Salix muriei Hultén, Lunds Univ. Arssk. n.f., Avd. 2, 39: 531. 1943.

Salix niphoclada Rydberg var. mexiae (C. R. Ball) Hultén, Ark. f. Bot. 7: 41. 1967.

Salix niphoclada Rydberg var. muriei (Hultén) Raup, Contr. Gray Herb., Harvard Univ, 185: 60. 1959.

Vegetative morphology. Plants 30–150(–300) cm high; shrubs; low shrubs, or mid shrubs; forming colonies by layering. Aerial stems erect, or decumbent, or prostrate. Branches grey-brown, or yellow-brown, or red-brown; not glaucous; glabrous, or hairy, or glabrescent; hairs pilose, or villous, or long-silky. Branchlets violet, or red-brown, or yellow-green, or yellow-brown; not glaucous; hairy; pilose, or villous, or tomentose, or with long-silky hairs. Branchlet hairs very dense, or moderately dense, or sparse; appressed, or spreading (straight, wavy, or geniculate). Buds arctica-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; deciduous in autumn, or persisting for 2 or more years; green; apex acute. Petioles 2–5.5 mm long (conspicuously short); shallowly concave in cross section; hairy; villous. Juvenile leaves yellowish green; hairy; abaxial surfaces hairs long-silky; abaxial hairs moderately dense, or very dense; abaxial hairs white. Leaf blade bases obtuse (slightly decurrent). Leaves not grass-like. Blades 13–64 mm long, length-width ratio 1.6–5.5, 6–14(–22) mm wide, oblong (narrowly oblong) or elliptic (narrowly to broadly elliptic) or lanceolate or obovate. Blade adaxial surface shiny, hairy, hairs villous, hairs moderately dense or sparse, hairs white, or translucent. Blade abaxial surface glaucous, hairy, hairs villous or woolly or pilose, hairs very dense or moderately dense or sparse, hairs white, hairs straight or wavy, hairs appressed or spreading. Blade margins slightly revolute. Blade margins entire and glandular-dotted (obscured by hairs); apices acute, or acuminate.

Reproductive morphology. Plants dioecious. Inflorescences catkins. Pedicels absent. Catkins flowering as leaves emerge. Male catkins 12–42 mm long; 4–14 mm wide; slender, or stout; peduncles 1.5–11 mm long (usually appearing sessile); borne on a flowering branchlet, or sessile; flowering branchlets 0–20 mm long. Female catkins 16–69 mm long; 4–13 mm wide; slender, or stout, or sub-globose; peduncles 2–14 mm long (usually appearing sessile); borne on a flowering branchlet; flowering branchlets 4–30 mm long. Floral bracts tawny, or brown, or black (sometimes greenish or suffused with red); 1.2–3.2 mm long; glabrous, or hairy all over; hairs sparse, or moderately dense; hairs wavy; apices rounded; apices entire. Flowers unisexual. Sepals absent. Petals absent. Stamens 2; stamen filaments glabrous, or hairy on lower half, or hairy at base only. Anthers purple becoming yellow, or yellow; ellipsoid, or sub-globose; 0.3–0.5 mm long. Male flowers abaxial nectaries present. Male flowers adaxial nectaries narrowly oblong, or oblong, or ovate; 0.5–1.5 mm long (0.87); nectaries distinct, or connate and cup-shaped. Female flowers abaxial nectaries absent. Female flowers adaxial nectaries narrowly oblong, or ovate; 0.5–2 mm long; longer than stipes. Ovary carpels 2. Stipes 0–0.5 mm long (ovaries almost sessile). Ovaries pear-shaped; slightly bulged below style, or abruptly tapering to style; hairy; villous, or long-silky. Ovary hairs very dense; white; spreading, or appressed; straight, or wavy; flattened. Styles 0.24–0.8 mm long. Stigma lobes 0.2–0.36–0.6 mm long. Ovules per ovary 8–20. Fruit a capsule; 4–6 mm long; hairy.

Chromosome information. 2n = 38.

2n (2x) = 38. Yurtsev et al. (1975, Chukotka); Petrovsky and Zhukova (1983a, Chukotka).

Ploidy levels recorded 2x.

Ecology and habitat. A shrub forming low thickets about 0.3 m tall, or growing as isolated erect or prostrate shrubs on calcareous, gravelly or sandy floodplains, terraces, eskers, and drumlins, or on fine, silty loess deposits. Its habitat may be wet to moderately well drained.

North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, continental Nunavut. Arctic islands: Banks, Victoria.

Northern hemisphere distribution. Amphi-Beringian. East Chukotka, West Alaska, North Alaska – Yukon, Central Canada, Labrador – Hudson Bay (western Hudson Bay lowlands).

General notes. Salix niphoclada is a low to sometimes prostrate shrub with small, elliptic leaves with very short petioles (barely longer than the bud), slender catkins, dark floral bracts, and almost sessile ovaries. This species has been treated as S. brachycarpa subsp. niphoclada (Argus 1965, 1973). Subspecies rank was proposed because the two taxa were thought to intergrade where their ranges overlap in northern British Columbia. The intergradation, however, is not strong and seems not to extend beyond the area of overlapping ranges. This situation is very similar to that described for S. lanata - S. richardsonii - S. calcicola, and S. planifolia - S. pulchra. 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 for intergradation is often indistinct, it appears most appropriate to use binomial nomenclature. Salix fullertonensis C.K. Schneider, used in Porsild (1957, 1964), is a synonym of Salix niphoclada Rydberg.

Hybrids

Salix glauca × S. niphoclada. This putative hybrid recombines the characteristics of the parental species. In 1965 Argus wrote, ‘Characteristics indicative of [S. niphoclada] are the short petioles, small narrowly elliptic-oblanceolate leaves with acute-attenuate apices, small stipules, and narrow, loosely flowered aments [catkins]. Characteristics suggesting S. glauca are the long petioles, large oblanceolate leaves, large stipules, and densely flowered, broadly cylindrical aments.’

Illustrations. • Habit and Habitat. A low, erect shrub growing at the base of cliffs. Alaska, Brooks Range. 15 July, 1989. • Habit and habitat. A low erect shrub with small elliptic leaves and very short petioles. N.W.T., Nicolson Island. July, 1997. Laurie Consaul 1153 and Lynn Gillespie. CAN. • Habit. A low erect shrub with catkins flowering as the leaf buds open. Note small elliptic leaves on very short petioles. N.W.T., Kitigazuit. Laurie Consaul 1159 and Lynn Gillespie. CAN. • Close-up of a branch of a female plant. Female plant with pilose elliptic leaves. Petioles are very short, barely exceeding the bud. N.W.T., Victoria Island. 18 August, 1987. • Close-up of female catkins. Female plant with pilose elliptic leaves. Petioles are very short, barely exceeding the bud. N.W.T., Kitigazuit. Laurie Consaul 1157 and Lynn Gillespie. CAN. • Close-up of female catkin. The catkin is slender and compact. The stipes are short and the ovaries are almost sessile on the rachis. N.W.T., Kitigazuit. Laurie Consaul 1157 and Lynn Gillespie. CAN. • Close-up of female catkin. The stipes are short and the ovaries are almost sessile on the rachis. N.W.T., Nicolson Island. Laurie Consaul 1153 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.

.

Contents