Flora of the Canadian Arctic Archipelago
English: Loose flowered alpine sedge,
French: Carex rariflore,
Inuktitut: Iviit, ivisuka, ivitsuskaka.
Cyperaceae, Sedge family.
Published in In Sowerby, Engl. Bot. 35: t. 2516. 1813.
Type: Norway: Norska Nordland vid Lyngenfjord, 08.07.1800, leg. Wahlenberg, selected by Moberg and Nilsson, Nord. J. Bot. 11: 291. 1991. Lectotype: UPS.
Synonymy. Carex limosa L. var. (gamma) rariflora Wahlenb., Kongl. Vetensk. Acad. Nya Handl. 24: 162. 1803.
Carex rariflora L. f. erecta Polunin, MS (Meddel. Grønland 1941.)
Carex pluriflora Hultén, Acta Univ. Lund. 2, 38(1): 367, fig. 4a-d. 1942.
Carex rariflora var. pluriflora ( Hultén ) B. Boivin, Naturaliste Canad. 94: 523. 1967.
Vegetative morphology. Plants (8–)10–20(–25) cm high; perennial herbs; not caespitose (stems sometimes loosely clustered). Only fibrous roots present. Roots tomentose furry, thick, and yellow; typical of sect. Limosae. Roots pallid-brown. Ground level or underground stems horizontal; stoloniferous; elongate, or compact. Ground level or underground stems scales present (on stolons). Aerial stems erect (red or purple-brown at the base); filiform (0.5–0.8 mm in diameter). Leaves present; mainly basal; alternate; marcescent. Petioles absent. Sheaths present; persisting (fibrous, sheath fronts membranous); not forming a conspicuous build-up at the base of the plant; brown, or reddish orange; sheath collars absent. Ligules present. Leaves grass-like. Blades 20–80 mm long, 0.5–2(–2.5) mm wide, straight, linear, flat or folded (loosely), veins parallel. Blade adaxial surface scabrous (at the tip). Blade margins scabrous (or coarsely ciliate to serrulate).
Reproductive morphology. Plants monoecious (rarely bisexual). Flowering stems two or more per plant. Flowering stems triangular in cross section. Flowering stems conspicuously taller than the leaves; with leaves. Leaf or reduced bract subtending the base of the inflorescence present; reduced, or scale-like; shorter than the apex of the inflorescence (terminating in a short blade); (5–)10–30 mm long; persistent; with sheath longer than the blade, or with sheath shorter than the blade. Inflorescences a raceme of spikes; 2.5–3(–4) cm long; 10–20 mm wide. Pedicels glabrous (and capillary). Cladoprophylls present. Inflorescence multispicate. Inflorescence 2–4 spikes (lateral spikes each with 2–10 pergynia, 6–15 mm long × 3.5–5 mm wide). Individual spike(s) erect (the terminal staminate spike), or pendent (the lateral pistillate spikes, each with 3–8 flowers). Terminal spike completely staminate (6–20 mm long × 1–2.5 mm wide; staminate scales oblanceolate to obovate, 3.2–4.8 × 1.5–2 mm, apex acute to obtuse; lateral spikes 6–15 mm long × 3.5–5 mm wide with 2–10 perigynia). Floral scales shorter than the perigynium in fruit; brown, or black; with margins the same colour as the body of the scale (midvein conspicuously pale); ovate (circular); (3–)3.5–4.5(–4.8) mm long; 2.8–3.2(–3.4) mm wide (broader than the perigynia); glabrous; apex obtuse, or cuspidate. Flowers unisexual. Staminate flowers conspicuous. Perianth represented by a perigynium. Sepals modified (but not a pappus). Stamens present (staminate flowers), or absent (pistillate flowers); 3. Anthers 2–2.5 mm long. Ovary superior; carpels 3; syncarpous. Perigynia sessile. Styles 3; partially fused; thick and short. Stigmas per ovary 3. Placentation basal. Ovules per ovary 1. Fruit surrounded by a perigynium. Perigynia fused to the apex except for a small aperture through which the style protrudes; broadly ovate; 2.5–4.5 mm long; 1.5–2 mm wide; erect or ascending; green (pale); membranous; surface dull; glabrous (over most of the surface, margins ciliate-serrulate distally); papillose; faintly veined (with 3–9 veins); with 2 keels; apices merely conical or rounded (0.5–1 mm long). Fruit sessile; dry; an achene; obovate; indehiscent. Achenes trigonous; filling the perigynia. Seeds 1; 1.7–2.2 mm long (× 1–1.3 mm wide).
Chromosome information. 2n = 50, 52, and 54.
2n = 50–54.
2n = 50. Sørensen and Westergaard, in Löve and Löve (1948, Greenland); Zhukova and Tikhonova (1973); Zhukova and Petrovsky (1977); Zhukova et al. (1977, northeastern Asia); Yurtsev and Zhukova (1978); Löve (1981d, central Canada); Malychev (1990);
2n = about 50. Taylor and Mulligan (1968, western Canada, as C. pluriflora); Löve (1970a, Iceland?); Hämet-Ahti and Virrankoski (1971, southern Alaska, as C. pluriflora);
2n = about 52. Jørgensen et al. (1958, Greenland); Knaben and Engelskjøn (1967, Norway);
2n = 54. Löve and Löve (1948, northern Europe); Pojar (1973, western Canada, as C. pluriflora).
Ecology and habitat. Substrates: wet meadows, hummocks, around the margins of ponds, marshes, along streams, tundra, seashores (on sand in swales); imperfectly drained moist areas, seepage slopes; sand, till, moss; with high organic content, peat (rarely); calcareous and acidic. This species occurs on alkaline till plains. In wet meadows, it is typically found with Carex aquatilis, Salix, and Petasites frigidus. In wet hummocky tundra, common associates are Ledum, Empetrum, Vaccinium, and Eriophorum.
North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago moderate. Common (in the Low Arctic). Low Arctic. Arctic islands: Baffin, Southampton, Coats, and Victoria (new records since Porsild (1957) and Simpson Peninsula).
Northern hemisphere distribution. Circumpolar, or circumboreal. Northern Iceland, Northern Fennoscandian, KaninPechora, Polar Ural Novaya Zemlya, YamalGydan, Taimyr Severnaya Zemlya, AnabarOlenyok, Kharaulakh, YanaKolyma, West Chukotka, South Chukotka, East Chukotka, West Alaska, North Alaska Yukon, Central Canada, Labrador Hudson Bay, West Greenland, East Greenland.
General notes. Polunin (1940, p. 127) noted that this species varies considerably in the length of the pedicels, "even the lowest of which may be so short [less than 1 cm long] and rigid as to hold the spike erect instead of pendulous, and so constitute f. erecta Polunin. The species also varies in the colour of the scales, which, except along the midrib, are generally of such a dark brown as to appear jet-black in the field; but they can be of almost any shade to quite a pale brown... This occurrence of forms with light-coloured scales in species that normally have them dark is almost general in this and closely related groups."
Vellend and Waterway (1999), in a study of geographic patterns of genetic diversity for C. rariflora, sampled from the east coast of James Bay, interior Nouveau-Québec, and the northern Yukon Territory. They found that within-population diversity was low overall, and that the degree of population differentiation was high. Particularly low levels of genetic variation at James Bay are attributed to founder events following postglacial colonisation. Higher genetic variation in the northern Yukon is attributed to the presence of glacial refugia during the Pleistocene.
Illustrations. • Habitat. Sedge meadow dominated by Carex rariflora. Nunavut, Baffin Island, Iqaluit. Aiken 97–031. CAN. Scale bar in cm. • Habitat. Plants growing on the margins of a stream near the markers have brown inflorescenses with spreading spikes. N.W.T., Tuktoyaktuk. Aiken and Brysting 01–083. Scale bar in cm. • Close-up of plants. Plants approximately 20 cm high, growing on the margins of a stream. N.W.T., Tuktoyaktuk. Aiken and Brysting 01–113. Scale bar in cm. • Close-up of inflorescence. Inflorescence with two lower pistillate spikes, and an upper staminate spike. Brown scales subtend the green perigynia that are larger than the scales resulting in a characteristically two-toned spike. N.W.T., Tuktoyaktuk. Aiken and Brysting 01–083. CAN. Scale bar in cm. • Close-up of inflorescence. Terminal spike staminate and lateral spike pistillate. Perigynia apex conical. There is a contrast in color between the floral scales and the perigynia. Nunavut, Baffin Island, Iqaluit. Aiken 97–031. CAN. • Arctic Island Distribution.
This publication is available on the internet (posted May 2011) and on CD-ROM (published in 2007). These versions are identical in content, except that the errata page for CD-ROM is accessible on the main index page of the web version.
Recommended citation for the web-based version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada, Ottawa. http://nature.ca/aaflora/data, accessed on DATE.
Recommended citation for the CD-ROM version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. [CD-ROM] NRC Research Press, National Research Council of Canada, Ottawa..