Salix planifolia Pursh.
Tea-leaf willow.
Fl. Lam. Sept. 2: 611. 1814
Salix phylicifolia subsp. planifolia (Pursh) Hiitonen
Salix plylicifolia var. planifolia (Pursh) Cronquist
Salix phylicifolia var. monica (Bebb) Jepson
Salix phylicifolia var. pennata (Ball) Cronq.
Salix planifolia var. nelsonii (Ball) Ball ex E.C. Sm.
Salix planifolia var. pennata (Ball) Ball ex Dutilly, Lepage & Daman
Plants low shrubs, or mid shrubs, or tall shrubs; more than 15 cm high; 150–400 cm high; not colonial. Stems. Aerial stems erect, or decumbent. Branches yellow-brown, or red-brown, or brownish (dark); not glaucous (sometimes to rarely glaucous); glabrous, or glabrescent; epidermis flaky. Branchlets yellow-brown, or red-brown, or brownish (dark); not glaucous (sometimes to rarely glaucous); glabrous, or hairy, or glabrescent; pubescent, or villous, or with short-silky hairs; hairs sparse, or moderately dense (rarely very dense); hairs appressed, or fishhook-curved, or spreading. Bud scale inner membrane free but not separating from outer membrane, or fused to outer layer. Stipules. Stipules present, or absent; leaf-like, or scale-like; brown, or green; apex acute. Petioles. Petioles 2–9(–13) mm long; glandular dots at the base of the leaf absent; shallowly concave in cross-section; glabrous, or hairy. Petioles adaxial surface pilose, or hairs short-silky. Leaves. Juvenile leaves reddish, or yellowish green; glabrous, or hairy; abaxial surface pubescent, or hairs long-silky (translucent); hair sparse, or moderately dense, or very dense; hair white, or gray. Blades 2–4.5(–6.5) cm long; 5–15(–23) mm wide; length-width ratio 1.5–4.7; herbaceous, or leathery; oblong (narrowly oblong), or elliptic (to narrowly elliptic), or oblanceolate; flat, or revolute (particularly at base); 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 highly glossy; glabrous, or hairy, or glabrescent; hairs short-silky; hairs sparse; hairs white and translucent. Blades abaxial surface glabrous, or hairy, or glabrescent; glaucous; hairs short-silky, hairs long-silky; hairs sparse; hairs white, or translucent, or mixture of white, or translucent, and rust-coloured, or rust-coloured; hairs appressed; hairs straight. Leaf bases acute (rarely rounded). Leaf margins entire and glandular-dotted, or serrulate, or crenate; with teeth toward base only, or all around leaf; with marginal glands, or with submarginal glands. Leaf margins with 2–8 glands per cm (4). Leaf apices acute.
Plants dioecious. Catkins. Catkins flowering before the opening of leaf buds; one to several catkins just below tip of previous year’s shoot. Male catkins. Male catkins densely flowered; 11–39(–50) mm long; 10–15 mm wide; stout, or subglobose; peduncles 0–6 mm long; sessile; flowering branchlets 0 mm long. Female catkins. Female catkins densely flowered; 15–63 mm long; 8–18 mm wide; slender, or stout; peduncles 0–9 mm long; sessile (rarely with bracts); flowering branchlets 0 mm long. Floral bracts. Floral bracts brown, or black; widest at base, or widest at middle, or widest toward tip; 1–3.2 mm long; hairy all over; hairs moderately dense, or very dense; hairs straight; entire. Stamens 2; filaments glabrous, or hairy at base only (sparsely so). Anthers purple becoming yellow; stout-cylindrical; axis straight; 0.5–0.7 mm long. Male flowers. Male flowers abaxial nectaries absent; adaxial nectaries one; adaxial nectaries slender-rod, or broad-rod; adaxial nectaries 0.4–0.8 mm long. Female flowers. Female flowers adaxial nectaries absent; unlobed; slender-rod, or broad-rod, or square, or ovate (tapering to slender tip); 0.4–1.3 mm long; shorter than stipes, or equal to stipes, or longer than stipes. Stipes 0.3–0.8 mm long. Ovaries pear-shaped; ovary slightly bulged at the base of the style, or gradually tapering to style; hairy; ovary hairs short-silky, or hairs long-silky. Ovary hair moderately dense, or dense; white, or translucent, or mixture of white, or translucent, and rust-coloured; appressed, or spreading; straight; flattened. Styles 0.5–2 mm long. Stigmas slender-cylindrical; lobes 0.36–0.52–0.92 mm long. Ovules 10–16. Fruit. Fruit (2.5–)5.5–6 mm long; glabrescent.
Chromosome inforamtion. 2n = 57 and 76. 3x Suda & Argus 1968, 1969. 4x Löve & Löve 1964, 1966, 1982, Löve et al. 1971, Suda & Argus 1968, 1969, Dorn 1975b. Ploidy levels recorded 3 & 4x.
Distribution. Northern hemisphere: St. Pierre and Miquelon, Canada, United States. Canada: Alta., B.C., Lab., Man., Nfld., Ont., Que., Sask., Yukon, N.W.T., Nunavut. USA: Ariz., Calif., Colo., Idaho., Maine, Mich., Minn., Mont., Nev., N.H., N.Mex., Oreg., S. Dak., Utah, Vt., Wash. (?), Wyo.
Ecology and habitat. A rare, but conspicuous, shrub, 0.6–4 m tall (Polunin 1940), of sheltered stream valleys and snow beds.
Notes. Salix planifolia is a low shrubby species that has small, usually ovate, non-persistent stipules, the catkins are sessile, the ovaries are glabrous, and the nectaries 0–3 times as long as the stipes. It is closely related to Salix pulchra which differs from it in having prominent, linear, persistent stipules.
This species has been treated as S. planifolia subsp. planifolia (Argus 1973). Subspecies rank was proposed because where the ranges of it and S. pulchra overlap in the Mackenzie Mountains and in northwestern British Columbia they appeared to intergrade. The intergradation, however, does not seem to extend beyond the overlapping populations. This situation is very similar to that described for S. lanata - S. richardsonii - S. calcicola, and S. brachycarpa - S. niphoclada. 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.
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Illustrations. • Plate. a. Vegetative branch. The swollen buds in the leaf axils are flower buds that will open the next spring. Scale bar = 1 cm. b. Female catkin. The catkin is sessile, lacking a flowering branchlet. Scale bar = 1 mm. c. Male flower. Scale bar = 1 mm. d. Base of male flower with the floral bract removed to show the adaxial nectary. Scale bar = 1 mm. e. Female flower. Scale bar = 1 mm. • 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).
