Salix herbacea L.
Snowbed willow.
Sp. pl. 2: 1018. 1753.
Plants dwarf shrubs; less than 15 cm high; 0.5–5 cm high; forming rhizomatous or stoloniferous mats. Stems. Aerial stems erect. Branches red-brown, or violet; not glaucous; glabrous; epidermis not flaky. Branchlets yellow-brown, or red-brown; not glaucous, or thinly glaucous; glabrous. Bud scale inner membrane fused to outer layer. Stipules. Stipules absent. Petioles. Petioles 1.5–6 mm long; glandular dots at the base of the leaf absent; convex to flat in cross-section, or deeply concave in cross-section, but margins not covering the groove; glabrous. Leaves. Juvenile leaves yellowish green; glabrous. Blades 0.6–2.1 cm long; 6–17 mm wide; length-width ratio 0.9–1.4; herbaceous, or leathery; circular, or elliptic (broadly elliptic to subcircular or wider than long); flat; secondary veins protruding on adaxial and abaxial surfaces; secondary veins mostly arising at or close to a single point at base and running in recurved arches toward leaf apex; stomata on both adaxial and abaxial surfaces. Blades adaxial surface shiny; glabrous. Blades abaxial surface glabrous; not glaucous. Leaf bases cordate, or truncate (subcordate). Leaf margins crenate (crenulate); with teeth all around leaf; with teeth per cm 7–20; with marginal glands. Leaf apices obtuse, or rounded.
Plants dioecious. Catkins. Catkins flowering with the opening of leaf buds; catkins terminal on previous year’s shoot. Male catkins. Male catkins loosely flowered (2–10-fl); 2–5.5 mm long; 1.5–5 mm wide; subglobose, or globose, or shape indeterminate; peduncles 0.25–2 mm long; borne on a flowering branchlet; flowering branchlets 0.25–2 mm long. Female catkins. Female catkins loosely flowered (2–11-fl); 3–11 mm long; 2–10 mm wide; subglobose, or globose, or shape indeterminate; peduncles 0.25–4 mm long; borne on a flowering branchlet; flowering branchlets 0.75–3.5 mm long. Floral bracts. Floral bracts tawny, or light rose, or brown; widest toward tip; 0.5–1.5 mm long; glabrous (fringed at apex); entire. Stamens 2; filaments glabrous, or hairy on lower half. Anthers purple becoming yellow; stout-cylindrical, or subglobose; axis straight; 0.3–0.6 mm long. Male flowers. Male flowers abaxial nectaries one; adaxial nectaries one; adaxial nectaries broad-rod, or ovate; adaxial nectaries 0.6–1.1 mm long; adaxial nectaries separate, or partially connected at base. Female flowers. Female flowers adaxial nectaries absent, or one; unlobed; slender-rod, or broad-rod; 0.3–1.1 mm long; longer than stipes, or shorter than stipes; nectaries separate. Stipes 0.28–1.12 mm long. Ovaries pear-shaped, or ovate; ovary abruptly tapering to style; glabrous. Styles 0.2–0.4 mm long (entire or bifid). Stigmas two plump lobes with continuous stigmatic surface, or broad-cylindrical; lobes 0.08–0.24–0.32 mm long. Ovules 12–18. Fruit. Fruit 2.2–7.5 mm long; glabrous.
Chromosome inforamtion. 2n = 38. Löve & Löve 1966, 1982. Ploidy levels recorded 2x.
Distribution. Northern hemisphere: Greenland, Canada, United States. Canada: Lab., Man., Nfld., N.W.T. (Frank.) (old), N.W.T. (Keew.) (old), Que., N.W.T., Nunavut. USA: Maine, N.H., N.York.
Notes. Salix herbacea is a dwarf species with most of its branching is underground (rhizomatous); often only the tips of the branchlets appear above the surface. Its leaves are broad, crenulate, and lack stipules; the catkins are short, few-flowered and borne at the tips of normal vegetative shoots.
The distribution of S. herbacea is amphi-Atlantic (Hultén 1958). Populations at the eastern end of Great Bear Lake and western end of Great Slave Lake appear to be small, disjunct populations. During the late-glacial period it was known to occur as far south in North America as Cambridge, Massachusetts, where leaves were found in a kettle moraine (Argus & Davis 1962).
An excellent report by Beerling (1998) dealing with all aspects of the biology, ecology, distribution, anatomy, morphology, taxonomy, etc. of Salix herbacea was written for the Biological Flora of the British Isles.
Hybrids
Salix × peasei Fern. (S. herbacea × uva-ursi). This hybrid combines that characters of the parental species. It is coarser than S. herbacea and has thick, trailing stems. Its leaves are crenate as in S. herbacea but its longer catkins resemble S. uva-ursi. Polunin (1940) reports it from Chesterfield Inlet and includes it in the key and illustrates in his Circumpolar Arctic Flora (Polunin 1959). This hybrid was described as a species of hybrid origin from Mt. Washington, New Hampshire (Fernald 1917), but most authors regard it as a hybrid.
Illustrations. • Habit. Salix herbacea: a dwarf shrub with stems intertwined in the tundra. Catkins are borne at the tips of the branches. They consist of a cluster of flowers borne on a short, leafy flowering branchlet with a pair of leaves. The leaves are glabrous, shiny and broadly elliptic to subcircular. This species is only one of two species in the Arctic, the other being S. reticulata, in which almost every vegetative shoot ends in a catkin. Photograph taken at Richmond Gulf, Quebec, 22 July 1983. • Habit. Salix herbacea: habit. Photograph taken at Bjornoya Island (Bear Island), Arctic Ocean, Norway by Jack Gillett, slide number 82316. • Habitat. Salix herbacea: plant forming a mat in moss on quartzite talus. Photograph taken at Richmond Gulf, Quebec, 22 July 1983. • Habit and Habitat. Salix herbacea: habit, scale bar in cm. Photo taken at Iqaluit, Baffin Island, Nunavut, Aug. 1997. Voucher specimen: Susan Aiken and Cheryl McJannet 97020, CAN. • Habit and Habitat. Salix herbacea: habit. Photograph taken at Bjornoya Island (Bear Island), Arctic Ocean, Norway by Jack Gillett, slide number 82316. • Plant close-up. Salix herbacea. Leaves turning yellow-orange in the fall. Photo taken at Nunavut, Baffin Island, Iqaluit. Susan Aiken 97–014. • 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).
