Salix niphoclada Rydb.
Barren-ground willow.
Bull. N.Y. Bot. Gard. 1: 272. 1899
Salix brachycarpa subsp. niphoclada(Rydb. ) Argus
Salix brachycarpa var. fullertonensis(C. Schneider) Argus
Salix fullertonensisC. Schneider
Salix brachycarpa var. mexiae Ball
Salix glauca var. niphoclada (Rydb.) Wiggins
Salix muriei Hultén
Salix niphoclada var. mexiae (Ball) Hultén
Salix niphoclada var. muriei (Hultén) Raup
Plants low shrubs, or mid shrubs; more than 15 cm high; 30–150(–300) cm high; not colonial. Stems. Aerial stems erect, or decumbent, or prostrate. Branches gray-brown, or yellow-brown, or red-brown; not glaucous; glabrous, or hairy, or glabrescent; woolly, or tomentose; epidermis flaky. Branchlets violet, or red-brown, or yellow-green, or yellow-brown; not glaucous; hairy; pilose, or villous, or with long-silky hairs; hairs very dense, or moderately dense, or sparse; hairs appressed, or fishhook-curved. Bud scale inner membrane fused to outer layer. Stipules. Stipules present; leaf-like, or scale-like; apex acute. Petioles. Petioles 2–5 mm long; glandular dots at the base of the leaf absent; shallowly concave in cross-section; hairy. Petioles adaxial surface villous. Leaves. Juvenile leaves yellowish green; hairy; abaxial surface hairs long-silky; hair moderately dense, or very dense; hair white. Blades 1.3–4.3 cm long; 6–14 mm wide; length-width ratio 1.6–3.8; herbaceous, or leathery; oblong (narrowly oblong), or elliptic (narrowly to broadly elliptic), or lanceolate, or obovate; revolute; secondary veins flat on adaxial surface, protruding on abaxial surface, or protruding on adaxial and abaxial surfaces; secondary veins arising along midrib; stomata only on abaxial surface, or stomata on both adaxial and abaxial surfaces. Blades adaxial surface shiny; hairy; hairs villous; hairs moderately dense, or sparse; hairs white and translucent. Blades abaxial surface hairy; glaucous; villous, hairs woolly, pilose; hairs very dense, or moderately dense, or sparse; hairs white, or translucent; hairs appressed, or spreading; hairs straight, or wavy. Leaf bases obtuse, or attenuate, or acute, or cuneate. Leaf margins entire and glandular-dotted (obscured by hairs); with teeth toward base only; with marginal glands. Leaf apices acute, or acuminate.
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 moderately densely flowered, or densely flowered; 6–37 mm long; 4–14 mm wide; slender, or stout, or subglobose; peduncles 0–5 mm long; borne on a flowering branchlet; flowering branchlets 0–12 mm long. Female catkins. Female catkins densely flowered, or moderately densely flowered; 11–55 mm long; 5–13 mm wide; slender, or stout; peduncles 2–14 mm long; borne on a flowering branchlet; flowering branchlets 3–25 mm long. Floral bracts. Floral bracts tawny, or brown, or black (sometimes greenish or suffused with red); widest at base, or widest at middle, or widest toward tip; 1.2–3.2 mm long; hairy all over; hairs sparse, or moderately dense; hairs wavy; entire. Stamens 2; filaments glabrous, or hairy at base only. Anthers purple becoming yellow; ellipsoid, or subglobose; axis straight; 0.3–0.5 mm long. Male flowers. Male flowers abaxial nectaries one; adaxial nectaries one; adaxial nectaries slender-rod, or broad-rod, or ovate; adaxial nectaries 0.5–1.2 mm long (0.87); adaxial nectaries separate. Female flowers. Female flowers adaxial nectaries absent; unlobed; slender-rod, or ovate; 0.5–2 mm long; longer than stipes. Stipes 0–0.5 mm long. Ovaries pear-shaped; ovary slightly bulged at the base of the style, or abruptly tapering to style; hairy; ovary villous, or hairs long-silky. Ovary hair dense; white, or translucent; spreading, or appressed; straight, or wavy; flattened. Styles 0.2–0.8 mm long. Stigmas slender-cylindrical, or broad-cylindrical; lobes 0.2–0.36–0.6 mm long. Ovules 12–20. Fruit. Fruit 4–6 mm long; glabrescent.
Chromosome inforamtion. 2n = 38. Yurtsev et al. 1975; Zhukova & Tikhonova 1973; Zhukova & Petrovsky 1987. Ploidy levels recorded 2x.
Distribution. Northern hemisphere: Canada, United States, Eurasia (Siberia). Canada: B.C., Yukon, N.W.T., Nunavut. USA: Alaska.
Ecology and habitat. A shrub forming low thickets about 0.3 m tall, or as isolated erect or prostrate shrubs on calcareous, gravelly or sandy floodplains, terraces, eskers, and drumlins, or on fine, silty loess deposits. It habitat may be wet to moderately well-drained.
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 where the ranges of the two taxa overlap in northern British Columbia they appeared to intergrade. The intergradation, however, is not strong and seems not to extend beyond the area of overlapping. 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, in-as-much as such nomenclature is cumbersome to use and is therefore often ignored by the non-taxonomist, its information value is minimal. This taken together with the fact that evidence of intergradation, on which the decision to use subspecific rank was based, is often indistinct suggests that it is best to use binomial nomenclature.
Hybrids
Salix glauca subsp. acutifolia × 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. Salix niphoclada: habit. Photo taken at Kitigazuit, N.W.T. by Laurie Consaul, Aug. & July 1997. Voucher specimen: Laurie Consaul and Lynn Gillespie 1159, CAN. • Habit and Habitat. Salix niphoclada: a low, erect shrub growing at the base of cliffs. Photograph taken at the Brooks Range, Alaska, 15 July 1989. • Habitat. Salix niphoclada: Photo taken in the N.W.T., Kitigazuit. Laurie Consaul and Lynn Gillespie 1156 & 1157. • Habit and habitat. Salix niphoclada: habit and habitat. Photo taken at Nicolson Island, N.W.T. by Laurie Consaul, July 1997. Voucher specimen: Laurie Consaul and Lynn Gillespie 1153, CAN. • Close-up of a branch of a female plant. Salix niphoclada: Female plant with pilose elliptic leaves. Petioles are very short, barely exceeding the bud. Photograph taken on Victoria Island, N.W.T., 18 Aug. 1987. • Close-up of three female catkins. Salix niphoclada: close-up of three female catkins. Photo taken at Kitigazuit, N.W.T. by Laurie Consaul, Aug. & July 1997. Voucher specimen: Laurie Consaul and Lynn Gillespie 1157, CAN. • Close-up of female catkin. Salix niphoclada: close-up of female catkin. The catkin is slender and compact. The stipes are short and the ovaries are almost sessile on the rachis. Photo taken at Kitigazuit, N.W.T. by Laurie Consaul, Aug. & July 1997. Voucher specimen: Laurie Consaul and Lynn Gillespie 1157, CAN. • Close-up of female catkin. Salix niphoclada. Photo taken in the N.W.T., Nicolson Island. Laurie Consaul and Lynn Gillespie 1153. • 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).
