Salix reticulata |
Salix nivalis |
|
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net-leaf willow, net-vein willow, netted willow |
dwarf snow willow, net-leaf willow, snow willow |
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Habit | Plants 0.03–0.15 m, (dwarf, forming clones by layering). | Plants 0.01–0.04 m, (dwarf, forming clonal mats by rhizomes). |
Stems | trailing; branches and branchlets yellow-brown or red-brown, glabrous. |
trailing or erect; branches yellow-brown or red-brown, glabrous or pubescent; branchlets yellow-brown or red-brown, glabrous or pilose. |
Leaves | stipules absent or rudimentary; petiole 3–46 mm, (sometimes glandular distally); largest medial blade amphistomatous or hemiamphistomatous, (2 pairs of secondary veins arising at or close to base, arcing toward apex), oblong, broadly oblong, broadly elliptic, subcircular, or circular, (8–)12–66 × 8–50 mm, 1–1.5 times as long as wide, base convex, rounded, subcordate, or cordate, margins slightly revolute, entire or crenulate (glandular-dotted), apex rounded, convex, or retuse, abaxial surface sparsely long-silky to glabrescent, adaxial (venation deeply impressed), slightly or highly glossy, glabrous or pilose; proximal blade margins entire; juvenile blade glabrous. |
stipules absent or rudimentary; petiole 1.5–7 mm (sometimes glandular distally or throughout); largest medial blade hypostomatous, (veins impressed-reticulate, 2 pairs of secondary veins arising at or close to base, arcing toward apex,), elliptic to broadly elliptic, 6–22 × 4–15 mm, 1.1–2.8 times as long as wide, base convex, rounded, subcordate, or cuneate, margins slightly revolute, entire (glandular-dotted), apex convex, rounded, or retuse, abaxial surface glabrous or with long-silky hairs, adaxial slightly glossy, glabrous; proximal blade margins entire; juvenile blade glabrous. |
Staminate flowers | abaxial nectary 0.5–0.9 mm, adaxial nectary oblong or ovate, 0.5–1 mm, nectaries connate and cup-shaped; filaments distinct, hairy on proximal 1/2 or throughout; anthers ellipsoid or globose, 0.3–0.4 mm. |
abaxial nectary 0.5–1.3 mm, adaxial nectary narrowly oblong, oblong, or square, 0.5–1.2 mm, nectaries connate and cup-shaped; filaments distinct, glabrous or hairy basally; anthers ellipsoid or shortly cylindrical, 0.4–0.6 mm. |
Pistillate flowers | abaxial nectary (0–)0.3–0.5 mm, adaxial nectary narrowly oblong, 0.5–1 mm, equal to or longer than stipe, nectaries distinct or connate and cup-shaped; stipe 0–0.8 mm; ovary pyriform or ovoid, short-silky, hairs flattened, beak abruptly tapering to styles; ovules 8–18 per ovary; styles connate to distinct 1/2 their lengths, 0.2–0.3 mm; stigmas flat, abaxially non-papillate with rounded tip, broadly cylindrical, or 2 plump lobes, 0.2–0.26–0.36 mm. |
abaxial nectary (0–)0.2–0.5 mm, adaxial nectary oblong, 0.2–1 mm, longer than stipe, nectaries distinct or connate and shallowly cup-shaped; stipe 0–0.8 mm; ovary obturbinate, short-silky, hairs flattened, beak abruptly tapering to styles; ovules 8–10 per ovary; styles distinct to connate 1/2 their lengths, 0.2–0.4 mm; stigmas flat, abaxially non-papillate with rounded tip, 0.2–0.26–0.36 mm. |
Capsules | 4.5–5 mm. |
3–4 mm. |
Catkins | staminate 11–54 × 4–9 mm, flowering branchlet 2–28 mm; pistillate densely flowered (more than 6 flowers), slender or stout, 11–79 × 3–8 mm, flowering branchlet 2–37 mm; floral bract tawny, 0.8–1.8 mm, apex rounded to retuse, entire, abaxially glabrous. |
staminate 7–19 × 2.5–6 mm, flowering branchlet 0.5–17 mm; pistillate densely to loosely flowered (4–17 flowers), stout, subglobose or globose, 7–21 × 2–9 mm, flowering branchlet 1–10 mm; floral bract tawny or light rose, 0.8–1.8 mm, apex rounded, entire, abaxially glabrous. |
2n | = 38. |
= 38. |
Salix reticulata |
Salix nivalis |
|
Phenology | Flowering early Jun-mid Aug. | Flowering late Jun-late Aug. |
Habitat | Arctic-alpine, polygonal tundra, dry tussock tundra, partially stabilized sand dunes, sedge meadows, Dryas tundra on alpine cliffs and ledges, snowbeds, stabilized talus slopes, white spruce woods, treed bogs | Alpine tundra, cirques, lake basins, rocky slopes and ridges, fellfields |
Elevation | 0-3500 m (0-11500 ft) | 1900-4000 m (6200-13100 ft) |
Distribution |
AK; CO; AB; BC; MB; NL; NT; NU; ON; QC; SK; YT; Europe; Asia (Chukotka, Russian Far East, arctic, e Siberia, Spitzbergen)
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CA; CO; ID; MT; NM; NV; OR; UT; WA; WY; AB; BC
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Discussion | The reported occurrence of Salix reticulata in Colorado (R. D. Dorn 1997) needs further study. Salix reticulata occurs in Europe in northern Scotland, northern Scandinavia, the Alps and other European mountains, and arctic Eurasia. The species is circumpolar except for Greenland and Iceland. A population of Salix reticulata on the Queen Charlotte Islands, with consistently glabrous ovaries, was named subsp. glabellicarpa. Some southeastern Alaska populations have plants with glabrous, partially hairy, and completely short-silky ovaries growing together. The possibility that subsp. glabellicarpa may be a hybrid or a simple mutation needs study. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Because geographic overlap is small and evidence of intergradation is tenuous, Salix nivalis is best treated as a species separate from S. reticulata; S. nivalis was previously treated as a subspecies of S. reticulata (G. W. Argus 1986b, 1991). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 65. | FNA vol. 7, p. 66. |
Parent taxa | Salicaceae > Salix > subg. Chamaetia > sect. Chamaetia | Salicaceae > Salix > subg. Chamaetia > sect. Chamaetia |
Sibling taxa | ||
Synonyms | S. reticulata var. gigantifolia, S. reticulata subsp. glabellicarpa, S. reticulata var. semicalva | S. nivalis var. saximontana, S. reticulata subsp. nivalis, S. reticulata var. saximontana |
Name authority | Linnaeus: Sp. Pl. 2: 1018. (1753) | Hooker: Fl. Bor.-Amer. 2: 152. (1838) |
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