Salix calcicola Fernald and Wieg.
Limestone willow.
Salicaceae, willow family.
Rhodora, 13: 251. 1911.
Salix lanata subsp. calcicola (Fernald and Wieg.) Hultén
Salix calcicola var. nicholsiana Polunin
Salix
richardsonii var. macouniana Bebb
Vegetative morphology. Plants shrubs; low shrubs; 10–30 cm high; not colonial. Aerial stems erect, or decumbent. Branches red-brown, or grey-brown, or yellow-brown; thinly glaucous, or not glaucous; glabrous, or hairy, or glabrescent (usually persistent); villous; epidermis flaky. Branchlets red-brown, or yellow-brown; not glaucous; hairy; villous; hairs moderately dense; hairs spreading. Bud scale inner membrane free and separating from outer membrane. Stipules present; leaf-like; apex acute, or obtuse, or rounded. Petioles 2–9 mm long; glandular dots at the base of the leaf absent; shallowly concave in cross-section, or convex to flat in cross-section; hairy; villous, or pilose. Leaf blade bases attenuate, or cordate, or acute. Juvenile leaves yellowish green, or reddish; hairy; abaxial surface villous (abaxial side only); hair moderately dense; hair white. Blades 17–61 mm long; 11–40 mm wide. Blades length-width ratio 0.7–2.6. Blades herbaceous, or leathery; elliptic (to subcircular); revolute, or flat (edges often purplish). Blades secondary veins impressed into adaxial surface, protruding on abaxial surface; arising along midrib. Blades adaxial surface dull; hairy. Blades adaxial surface hairs villous, or pilose; moderately dense; white and translucent. Blades abaxial surface glaucous; glabrous, or hairy, or glabrescent. Blades abaxial surface hairs sparse. Blades abaxial surface pilose, or villous. Blades abaxial surface hairs white, or translucent hairs; straight; spreading. Blade margins entire and glandular-dotted, or serrulate; with submarginal glands; with teeth all around the blade, or toward the base; with teeth per cm 6–18 (11). Blade margins with glandular hairs all around leaf, or toward base only. Leaf apices obtuse, or rounded, or acute.
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. Male catkins densely flowered; 18–45 mm long; 13–21 mm wide; stout, or subglobose; peduncles 0 mm long; sessile; flowering branchlets 0 mm long. Female catkins densely flowered; 22–80 mm long; 12–25 mm wide; stout, or subglobose; peduncles 0–7 mm long; sessile, or borne on a flowering branchlet (rarely on flowering branchlets); flowering branchlets 0 mm long. Floral bracts brown, or black; widest at middle, or widest at base; 1.2–3.2 mm long; hairy all over. 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; 0.5–0.7 mm long. Male flowers abaxial nectaries absent; adaxial nectaries one; adaxial nectaries slender-rod, or broad-rod; adaxial nectaries 0.5–0.8 mm long. Female flowers adaxial nectaries absent; unlobed; broad-rod; 0.6–1 mm long; longer than stipes, or equal to stipes (rarely shorter). Stipes 0.2–1.2 mm long. Ovaries pear-shaped, or inverse club-shaped; ovary gradually tapering to style; glabrous. Styles 1.6–3 mm long. Stigmas broad-cylindrical, or slender-cylindrical; lobes 0.2–0.38–0.56 mm long. Ovules 16–18. Fruit a capsule. Fruit 4.4–8 mm long; glabrous.
Chromosome information. 2n = 38. 38 (2x). - Löve and Löve (1982 arctic Canada). Ploidy levels recorded 2x.
Distribution. Northern hemisphere distribution: Canada. Arctic Islands: Baffin, King William, Southampton, Coats (Boothia Peninsula).
Ecology and habitat. Habitats: Forming small thickets, about 0.5 m tall, on calcareous substrate. Usually in wet, stony or gravely places, rubble above high tide, and stream margins; but also on sandy and silty shores of brooks, low dunes, and clay frost boils.
Notes. Salix calcicola is a low, erect shrub. The leaves are
usually broad to subcircular, the margins are usually minutely toothed, the
stipules are small and usually ovate, the catkins are sessile, the ovaries are
glabrous, and the stipes and styles long.
This species has been treated as
S. lanata subsp. calcicola (Hultén 1968). Subspecies rank
was proposed because where the two taxa overlap in the eastern Arctic they were
thought to intergrade. The intergradation, however, is not clear and
hybridization between S. calcicola and S. richardsonii is not
established. This situation is very similar to that found in S. lanata -
S. richardsonii, S. lanata - 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 or non-existent suggests
that it is best to use binomial nomenclature.
Hybrids
Salix
calcicola × richardsonii (Polunin 1940). Polunin described S.
richardsonii var. mckeandii (1940) and S. calcicola var.
nicholsiana (1938) which he thought were hybridizing and intergrading on
Baffin and Southampton islands. I have seen some suggestion of hybridization
between S. calcicola and S. richardsonii on Southampton Island,
but I have not seen clear evidence of hybridization elsewhere. This problem
requires field study.
Illustrations. • Habit. Salix calcicola: plant growing as a low erect shrub in a "sedge" meadow. Photograph taken at Iqaluit, Baffin Island, Nunavut, by Jack Gillett, 25 July 1982. Voucher specimen: Jack Gillett 19060, CAN. • Habit. Salix calcicola: plant prostrate on limestone gravel. Photograph taken at Pointe Riche, Newfoundland, 23 June 1969. • Close-up of stigmas. Surface view of female catkin with individual flowers with a single style and two stigmas that are rebranched. Nunavut, Baffin Island, Iqaluit. Aiken and Mallory 02–002b. • Close-up of young male catkin. Surface view of male catkin showing bright red pre-anthesis anthers among sikly hairs. Aiken and Mallory, 02–002b. CAN. • Close-up of a female catkins. Salix calcicola: Female catkins showing flowers with glabrous ovaries and pilose or villous, broadly elliptic leaves. Photograph taken at Iqaluit, Baffin Island, Nunavut, by Jack Gillett, 25 July 1982. Voucher specimen: Jack Gillett 19060, CAN. • 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).
