Flora of the Canadian Arctic Archipelago
English: Bicoloured sedge,
French: Carex bicolore,
Inuktitut: Iviit, ivisuka, ivitsuskaka.
Cyperaceae, Sedge family.
Published in Fl. Pedm. 2: 267. 1785.
Vegetative morphology. Plants (3.5–)7–12(–20) cm high; perennial herbs; caespitose; loosely tufted in several tufts. Only fibrous roots present. Roots pallid-brown. Ground level or underground stems horizontal; compact. Ground level or underground stems scales absent. Aerial stems erect, or decumbent; filiform (0.2–0.3 mm in diameter). Leaves mainly basal; alternate; marcescent. Petioles absent. Sheaths present; breaking down into fibres; not forming a conspicuous build-up at the base of the plant; green (soon fading to pallid-brown); sheath collars absent. Ligules present. Leaves grass-like. Blades 10–60(–70) mm long, 0.5–1(–2) mm wide (flat), straight, linear, strongly keeled, veins parallel. Blade adaxial surface glaucous, glabrous. Blade abaxial surface glaucous, glabrous. Blade margins scabrous (scaberulous at the tip); apices acuminate.
Reproductive morphology. Plants monoecious. Flowering stems triangular in cross section. Flowering stems about as high as the leaves, or conspicuously taller than the leaves; with leaves. Leaf or reduced bract subtending the base of the inflorescence present (equalling or slightly longer than the inflorescence); conspicuous and leaf-like (rarely to 5 mm long), or reduced, or scale-like (usually); shorter than the apex of the inflorescence; 2–10 mm long; persistent; with sheath shorter than the blade, or sheathless. Inflorescences a spike of spikes; 1–1.5 cm long; 5–10 mm wide. Pedicels glabrous. Cladoprophylls present. Inflorescence multispicate. Inflorescence 2–3 spikes. Individual spike(s) ascending (spikes with 5–10(-25) perigynia, 5–12 mm long × 3.5–5.5 mm wide). Terminal spike staminate at the base (usually less than 1/3 flowers staminate; staminate portion 1–1.8 mm wide). Floral scales shorter than the perigynium in fruit; brown, or black (reddish); with margins darker in colour than the midvein (usually black with a green midvein); ovate (circular); 1.9–2.5(–3.8) mm long; 1.2–1.4(–1.7) mm wide; glabrous; apex obtuse (sometimes slightly mucronate). Flowers unisexual. Staminate flowers inconspicuous. Perianth represented by a perigynium. Stamens present (staminate flowers), or absent (pistillate flowers); 3. Anthers 1.3–1.6 mm long. Ovary superior; carpels 3; syncarpous. Perigynia sessile. Styles 2; partially fused; slender, extending beyond the beak. Stigmas per ovary 2. 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, or elliptic; 1.8–2.2(–3) mm long; 1.1–1.5(–1.8) mm wide; erect or ascending; whitish, or green; membranous; surface dull; glabrous; papillose (densely, seen at 10–40×); appearing veinless (or very finely nerved); with 2 keels; apices merely conical or rounded. Fruit sessile; dry; an achene; obovate; indehiscent. Achenes lenticular; filling the perigynia. Seeds 1.
Chromosome information. 2n = 48 or 50, 52.
2n = about 48. Löve and Löve (1956, Iceland, not included by Löve and Löve 1975);
2n = 50. Davies (1956a, 1956b); Schmidt, in Löve and Löve (1961a); Löve (1970a, Iceland); Zhukova and Tikhonova (1973, Chukotka);
2n = 52. Löve (1981d, central Canada); Hedberg (1967, northern Canada); Knaben and Engelskjøn (1967, southern and northern Norway); Yurtsev and Zhukova (1978, eastern Chukotka; Dalgaard (1989, western Greenland);
2n = about 52. Jørgensen et al. (1958, Greenland);
The low-ploidy central European chromosome count of 2n = 16 (Reese 1953) is strange, as this species is not easily mistaken (Elven et al. 2003).
Ecology and habitat. Substrates: seashores (on upper sandy beaches); imperfectly drained moist areas; sand, silt; with low organic content; calcareous. Typically found in small patches with other Carex. Not infrequent around the margins of pools in wet sand where there is little competition from plants of ranker growth. It is also found on patches of bare, wet mud and in open areas in marshes.
North American distribution. Alaska, Yukon, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago limited. Uncommon. Low Arctic, alpine (in Asia, central Europe, and Western North America). Arctic islands: Baffin, Southampton, Coats.
Northern hemisphere distribution. Circumpolar, or circumboreal (arctic-alpine, with large gaps). Northern Iceland, KaninPechora, Polar Ural Novaya Zemlya, West Chukotka, East Chukotka, West Alaska, North Alaska Yukon, Central Canada, Labrador Hudson Bay, West Greenland, East Greenland.
General notes. Polunin (1940) described this species as "a characteristic and attractive little sedge, with more or less pendulous spikes of rounded, pastel-green fruits peeping out from behind dark scales". He noted that it varies considerably in luxuriance and has culms that arch in all directions.
Illustrations. • Habitat. Delicate plants less than 10 cm high. Growing under willows in an area that has standing water in the spring. Nunavut, Southampton Island, Coral Harbour. Aiken and Brysting 01–083. CAN. • Close-up of plants. Delicate plants less than 10 cm high. Nunavut, Southampton Island, Coral Harbour. Aiken and Brysting 01–083. CAN. • Close-up of inflorescence. a. Arrow points to anther showing the position of inconspicuous staminate flowers at base of terminal spike. b. Pistillate flowers on distal part of terminal spike, perigynia with two stigmas. Note the "bi-coloured" scales. Aiken and Brysting 01–083. 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..