Salix pulchra Cham.
Diamond-leaf willow.
Salicaceae, willow family.
Linnaea 6: 543. 1831
Salix phylicifolia subsp. pulchra (Cham.) Hultén
Salix phylicifolia var. subglauca (Anderss.) Boivin
Salix phylicoides Anderss.
Salix planifolia subsp.
pulchra (Cham.) Argus
Salix planifolia var. yukonensis
(Schneid.) Argus
Salix pulchra var. looffiae Ball
Salix
pulchra var. palmeri Ball
Salix pulchra var.
yukonensis Schneid.
Vegetative morphology. Plants shrubs; low shrubs, or mid shrubs, or tall shrubs; 10–30(–450) cm high; not colonial. Aerial stems erect. Branches red-brown, or brownish; not glaucous (rarely glaucous); glabrous, or hairy, or glabrescent; villous (in patches); epidermis flaky. Branchlets brownish; not glaucous (rarely glaucous); glabrous, or hairy; villous, or puberulent; hairs sparse, or moderately dense, or very dense; hairs spreading. Bud scale inner membrane free but not separating from outer membrane. Stipules present (persist 2–4 yrs); leaf-like; apex acuminate. Petioles 2.8–10(–15) mm long; glandular dots at the base of the leaf absent; convex to flat in cross-section; glabrous, or hairy; puberulent (sparse). Leaf blade bases acute, or cuneate. Juvenile leaves yellowish green; glabrous, or hairy; abaxial surface pubescent; hair sparse; hair white, or grey. Blades (22–)32–60(–75) mm long; (8–)10–23(–26) mm wide. Blades length-width ratio (1.7–)2–3.6(–4.7). Blades herbaceous, or leathery; elliptic (to narrowly elliptic), or obovate; flat, or revolute. Blades secondary veins flat on adaxial surface, protruding on abaxial surface; arising along midrib. Blades adaxial surface shiny, or highly glossy; glabrous. Blades abaxial surface glaucous; glabrous (midrib with wh and ferr hairs). Blade margins entire and glandular-dotted, or crenate; with submarginal glands, or with marginal glands; with teeth all around the blade, or toward the base; with teeth per cm 2–5 (3). Blade margins with glandular hairs all around leaf, or toward base only. Leaf apices acute, or retuse, or acuminate.
Reproductive morphology. Plants dioecious. Flowering stems present. Inflorescence a catkin. Catkins flowering before the opening of leaf buds; one to several catkins just below tip of previous year’s shoot, or numerous catkins just below tip of previous year’s shoot. Male catkins densely flowered; 15–45 mm long; 12–19 mm wide; stout; peduncles 0–5 mm long; sessile; flowering branchlets 0 mm long. Female catkins densely flowered; 25–80 mm long; 8–19 mm wide; stout, or subglobose; peduncles 0–8 mm long; sessile (sometimes 2–3 bracts); flowering branchlets 0 mm long. Floral bracts brown, or black; widest at base; 1.6–2.8 mm long; hairy mainly at apex. Floral bracts hairs moderately dense; straight. Floral bracts entire. Perianth absent. Flowers unisexual. Stamens 2; filaments glabrous. Anthers purple becoming yellow; ellipsoid, or stout-cylindrical; axis straight; 0.4–0.8 mm long. Male flowers abaxial nectaries absent; adaxial nectaries one; adaxial nectaries slender-rod, or broad-rod; adaxial nectaries 0.6–0.9 mm long. Female flowers adaxial nectaries absent; unlobed; slender-rod, or broad-rod; 0.4–1.6 mm long; longer than stipes. Stipes 0.2–0.8 mm long. Ovaries pear-shaped; ovary slightly bulged at the base of the style; hairy; hairs long-silky. Ovary hairs moderately dense, or sparse; white, or translucent, or a mixture of white, or translucent, and rust-coloured; appressed; straight; flattened. Styles 1–1.8 mm long. Stigmas slender-cylindrical; lobes 0.44–0.63–0.96 mm long. Ovules 12–18. Fruit a capsule. Fruit 3.2–5.6 mm long; glabrescent.
Chromosome information. 2n = 76. 76 (4x). - Zhukova (1967, 1968, 1969 north eastern Asia); Johnson and Packer (1968 northwestern Alaska, two counts); Suda and Argus (1969 Alaska, three counts); Zhukova and Petrovsky (1971, 1987a north eastern Asia); Zhukova et al. (1977 north eastern Asia); Petrovsky and Zhukova (1983 north eastern Asia). Ploidy levels recorded 4x.
Distribution. Northern hemisphere distribution: Canada, United States, Eurasia (Russia). Arctic Islands: Banks.
Ecology and habitat. Habitats: In our area this rare shrub forms low thickets along river, lake, and streams.
Indigenous knowledge. Anderson (1939) noted that at that time in Alaska this species was used as food. The young shoots and catkins were used fressh and in seal oil and also stored in oil for winter use. The bark would be peeled off and the cambium scaped off and eaten.
Notes. Salix pulchra is a shrubby species with prominent,
persistent, linear stipules; the catkins are essentially sessile, the ovaries
are glabrous, and the nectaries 2–3 times as long as the stipes.
It is
closely related to S. planifolia which differs from it in having smaller,
usually ovate or short-linear, non-persistent stipules. It similar to and
sometimes difficult to separate from S. richardsonii based on vegetative
material. The two overlap on Banks Island. They are easily separated there,
however, by ovaries of Salix pulchra silky and those of S.
richardsonii glabrous.
This species has been treated as S.
planifolia subsp. pulchra (Argus 1973). Subspecies rank was proposed
because where the ranges of the two taxa 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 found in 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.
This species, along with S. alaxensis and
S. richardsonii, are the tallest growing willows in the Arctic
Archipelago. In the Masik River valley, south-western Banks Island, it forms a
dominant shrub tundra in association with S. alaxensis and S.
richardsonii (Kuc 1970, 1974).
Illustrations. • Line drawing. Salix pulchra: A. Male catkins are sessile on the branch. B. Male flowers have 2 stamens, a floral bract with long straight hairs, and a single nectary. C. Female catkins are sessile on the branch. D. Female flowers have a villous ovary with a long style, a long hairy floral bract, and a single floral nectary that is longer than the stipe. E. Leaves are typically oblanceolate and have linear, leaf-like stipules. • Arctic Island Distribution.
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, L.J. Gillespie, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, A.K. Brysting and H. Solstad. 1999 onwards. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).
