Flora of the Canadian Arctic Archipelago
English: Rock sedge,
French: Carex à écailles rousses, carex des rochers,
Inuktitut: Iviit, ivisuka, ivitsuskaka,
Cyperaceae, Sedge family.
Published in Fl. Pedem. 2: 264. 1785.
Type: Allioni, Fl. Pedem. 2, tab. 92, 1785. fig. 1, selected by Egorova (1999?). Lectotype.
Synonymy. Carex drummondiana Dewey, Amer. J. Sci. 29: 251.t.V.f. 82. 1836.
Vegetative morphology. Plants (4–)8–15(–20) cm high; perennial herbs; caespitose; loosely tufted in several tufts (with short cord-like rhizomes between the tufts). Only fibrous roots present. Ground level or underground stems horizontal; rhizomatous, or stoloniferous (cord-like, brown or black); elongate. Ground level or underground stems scales present. Aerial stems erect; not filiform (rather coarse, 0.3–1.2 mm in diameter). Leaves present; mainly basal (compact plants), or distributed along the stems (tall plants); alternate; marcescent. Petioles absent. Sheaths present; persisting; forming a conspicuous build-up at the base of the plant, or not forming a conspicuous build-up at the base of the plant; brown, or reddish orange; sheath collars absent. Ligules present (up to 1.5 mm long, apex ovate). Leaves grass-like. Blades 20–120(–150) mm long, 0.5–2.5(–3) mm wide (when flat, 0.5 mm wide when loosely rolled), somewhat curled, linear, channelled (tips soon becoming brown and dry), veins parallel. Blade adaxial surface glabrous or scabrous (scaberulous seen at 40×). Blades not lobed. Blade margins entire, scabrous (scaberulous).
Reproductive morphology. Plants monoecious. Flowering stems triangular in cross section. Flowering stems about as high as the leaves; without leaves. Leaf or reduced bract subtending the base of the inflorescence absent. Inflorescences spicate (a single spike 8–20 mm long × 1.5–4 mm wide); (0.6–)1–2 cm long; 5–10 mm wide. Inflorescence unispicate. Inflorescence with 3–15 pistillate flowers. Individual spike(s) erect. Terminal spike staminate at the apex (staminate scales brown, margins hyaline, midvein paler, oblong-lanceolate to obovate 2.5–3.5 mm long × 1.4–2 mm wide; spike with a 3–15 pistillate flowers at the base). Floral scales longer than the perigynium in fruit (usually); brown (at the base, hyaline at the apex); with margins and sometimes midvein paler in colour than the adjacent area of the scale; ovate (to circular); (2.5–)3–3.5(–4) mm long; 1.5–2.6(–3) mm wide; glabrous; apex obtuse (often concealing perigynia). Flowers unisexual. Staminate flowers inconspicuous. Perianth represented by a perigynium. Stamens present (staminate flowers), or absent (pistillate flowers); 3. Anthers 1.8–2.2 mm long. Ovary superior; carpels 3; syncarpous. Perigynia contracted at the base into a stipe. Styles 3; partially fused; long and thick (extending beyond the beak). 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; obovate (oblanceolate); (2.5–)2.8–3.5(–4) mm long; (1.4–)2–2.6(–2.9) mm wide; erect or ascending; golden brown (pale towards the base); membranous; surface dull; glabrous; faintly veined; apices merely conical or rounded. Fruit sessile; dry; an achene; ovoid, or obovate (2.2–2.5 × 1.5 mm); indehiscent. Achenes trigonous; filling the perigynia. Seeds 1.
Chromosome information. 2n = 50 and 52.
2n = 50 and 52.
2n = 50. Heilborn (1924, northern Norway); Flovik (1943, Svalbard?); Löve and Löve (1956, Iceland); Favarger (1959a, central Europe); Petrovsky and Zhukova (1978);
2n = about 50. Holmen (1952, Greenland); Murín (1978, central Europe);
2n = 52. Löve (1981d, northern Canada); Jørgensen et al. (1958, Greenland); Knaben and Engelskjøn (1967, Norway); Zhukova and Petrovsky (1971, northeastern Asia; 1987a, northeastern Asia); Druskovic (1995, southeastern Europe);
2n = about 52. Johnson and Packer (1968, northwestern Alaska).
Ecology and habitat. Substrates: river terraces (older and raised), tundra, slopes, ridges; dry; gravel, sand, silt, till (or in various combinations of the above; occasionally also near bedrock outcrops); with low organic content, peat (older dry deposits); calcareous. This species occurs on dry barrens or tundra where it is found with Dryas, Oxyria, Astragalus, and Poa species. On steeper slopes, it is found with Carex nardina and Saxifraga. This species is associated with the following geological features: till plains, old lake beds with thick peat deposits, sand and gravel morainal systems, drumlin ridges, and gravel kames.
Ball (in Ball et al. 2002) noted that C. rupestris can be confused with C. obtusata if collected without the rhizomes. They may be distinguished by the presence of reddish dots on the sheath fronts of the culm leaves in C. obtusata and the absence of dots in C. rupestris.
North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago widespread. Common. Arctic, alpine. Arctic islands: Baffin, Devon, Ellesmere, Axel Heiberg, Banks, Victoria, and Parry islands (Melville), Somerset, King William, Southampton (and Igloolik).
Northern hemisphere distribution. Circumpolar, or circumboreal (arctic-alpine). Northern Iceland, Northern Fennoscandian, KaninPechora, Svalbard Franz Joseph Land, Polar Ural Novaya Zemlya, YamalGydan, Taimyr Severnaya Zemlya, AnabarOlenyok, Kharaulakh, YanaKolyma, West Chukotka, Wrangel Island, South Chukotka, East Chukotka, West Alaska, North Alaska Yukon, Central Canada, Labrador Hudson Bay, Ellesmere Land Peary Land, West Greenland, East Greenland.
General notes. Polunin (1940) considered this taxon relatively common and noted that it varies considerably in size according to the local conditions, but not in any character that is of taxonomic importance.
In a study of scale-dependent correlations of Arctic vegetation and snow cover in southeastern Victoria Island, Schaefer and Messier (1995) found that C. rupestris was associated with low snow cover.
Illustrations. • Habitat. The dominant species in a transition zone between tundra and a small marsh. Nunavut, Ellesmere Island, 79°25'N, 75°38'W. Aiken 98–030. CAN. Photograph by Mollie MacCormac. • Habitat. Scruffy, rhizomatous sedge growing between the markers and on the adjacent dry rocky hillside. Nunavut, Baffin Island, Ogac Lake, Inner Basin. 11 July, 2004. Aiken and LeBlanc 04–056. CAN. • Close-up of plant. Unispicate sedge with marcescent leaves growing on a dry hillside. Nunavut, Baffin Island, Ogac Lake, Inner Basin. 11 July, 2004. Aiken and LeBlanc 04–056. CAN. • Herbarium specimen. Note long underground stems and somewhat curled leaves. CAN 204808. • Close-up of plants. Left, inflorescence with two mature, almost beakless perigynia. Right, younger inflorescence with anthers at the apex. Nunavut, Ellesmere Island, 79°25'N, 75°38'W. Aiken 98–030. CAN. Photograph by Mollie MacCormac. • Close-up of inflorescence. Unispicate inflorescence with staminate flowers at the apex and pistillate flowers at the base. CAN 484975. • Close-up of inflorescence. Unispicate inflorescence with several staminate flowers at the apex and a few pistillate flowers with long beaks and three stigmas below. Nunavut, Baffin Island, Ogac Lake, Inner Basin. 11 July, 2004. Aiken and LeBlanc 04–056. 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..