Flora of the Canadian Arctic Archipelago

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S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, L.J. Gillespie, A.K. Brysting, H. Solstad, and J.G. Harris

Kobresia simpliciuscula (Wahlenb.) Mack. subsp. subholarctica T.V. Egorova

English: Arctic kobresia,

French: Kobrésie simple,

Inuktitut: Iviit, ivisuka, ivitsuskaka.

Cyperaceae, Sedge family.

Published in Novosti Sist. Vyssh. Rast. 20: 83 1983.

Synonymy. Kobresia subholarctica (T.V. Egorova) T.V. Egorova, Bot. Zhurn. (Moscow and Lenningrad) 76: 1736. 1992.

Kobresia simpliciuscula (Wahlenb.) Mack. var. americana Duman, Bull. Torrey Bot. Club 83: 194. 1956.

Vegetative morphology. Plants 3–20(–25) cm high; perennial herbs; caespitose; in dense single compact tufts. Only fibrous roots present. Roots pallid-brown, or black. Ground level or underground stems absent. Aerial stems erect; not filiform (0.5–1 mm in diameter). Leaves mainly basal; alternate; dying annually and non-persistent, or marcescent (sheaths). Petioles absent. Sheaths present; persisting; forming a conspicuous build-up at the base of the plant (not shiny); reddish orange (brown, dull, base of blade usually persistent); sheath collars absent. Ligules present; 0.1–0.2 mm long. Leaves grass-like. Blades 20–100(–200) mm long, (0.2–)0.6–1.5(–2) mm wide. Leaves filiform. Blades straight, linear, folded or channelled, veins parallel, midvein similar in size to other veins in the leaf. Blade adaxial surface glabrous. Blade abaxial surface glabrous. Blade margins scabrous; apices acuminate.

Reproductive morphology. Plants monoecious. Flowering stems two or more per plant. Flowering stems circular or oval in cross section. Flowering stems about as high as the leaves, or conspicuously taller than the leaves; with leaves, or without leaves. Leaf or reduced bract subtending the base of the inflorescence absent. Inflorescences spicate; linear (rarely), or ovate; 0.8–1.5 cm long; 3–10 mm wide. Inflorescence multispicate. Inflorescence 2–7 spikes (few flowered, secondary spikes contracted into a lax head-like inflorescence, in tall specimens the lowermost spike is somewhat remote). Individual spike(s) erect, or ascending. Terminal spike staminate at the apex (proximal spikelets 1 flowered and pistillate, or 2-flowered and with a staminate flower at the base). Floral scales orange-brown; with margins and sometimes midvein paler in colour than the adjacent area of the scale, or with margins paler than body of the scale (margins hyaline, midvein distinct almost to the tip); lanceolate; 2.3–2.6 mm long; 1.3–1.7 mm wide; glabrous; apex acute (apex obtuse to sub-acute). Flowers unisexual, or bisexual (pistillate). Perianth represented by a perigynium. Sepals modified (but not a pappus). Stamens 3. Anthers (1–)1.3–1.6(–2) mm long. Ovary carpels 3; syncarpous. Perigynia sessile. Styles 3; long and thick (black and longer than the floral scales). Stigmas per ovary 3. Placentation basal. Ovules per ovary 1. Fruit surrounded by a perigynium. Perigynia open on one side; lanceolate, or broadly ovate; 1.9–2.3 mm long; 0.8–1.2 mm wide; erect or ascending; brown; membranous; surface dull; glabrous; appearing veinless; apices without a beak. Fruit sessile; dry; an achene (narrowly obovoid); ellipsoid (narrowly); yellowish (brown towards the tip); 2–3 mm long; 0.7–0.8 mm wide; indehiscent. Achenes trigonous; not filling the upper part of the perigynia. Seeds 1.

Chromosome information. 2n = 70-76.

2n = 72. Sørensen and Westergaard, in Löve and Löve (1948, Greenland);

2n = 70–75. Jørgensen et al. (1958, Greenland) changed to 2n = about 74, by Löve and Löve 1975);

2n = 72–76. Johnson and Packer (1968, Alaska);

2n = 76. Yurtsev and Zhukova (1978, eastern Chukotka; 1982, northern Siberia); Löve (1981d, northern Canada); Zhukova and Petrovsky (1987b, northeastern Asia).

Ecology and habitat. Substrates: around the margins of ponds, marshes, river terraces, tundra, slopes (rocky), seashores (on tidal flats); seepage slopes, imperfectly drained moist areas (wet tundra, wet clay by lakeshores, imperfectly drained glacial till plains, summer dry ponds); rocks, gravel, till; with low organic content, with high organic content, peat (older, dry); acidic, or circum-neutral. Typically local and rare. Found in marshes with Carex rariflora and C. capillaris, on seepage slopes with Trichophorum cespitosum and Saxifraga aizoides, and on dry peaty tundra with Dryas.

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. Uncommon. Arctic, alpine. Arctic islands: Baffin, Devon, Ellesmere, Victoria, and Southampton.

Northern hemisphere distribution. Circumpolar, or circumboreal. Svalbard – Franz Joseph Land, Anabar–Olenyok, Kharaulakh, 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) observed that K. simpliciuscula prefers less dry and exposed places than does K. myosuroides, often growing in quite damp meadows among grasses. It grows most frequently to about 12 cm high but sometimes exceeds 25 cm or, in unfavourable situations, may be as short as 4 cm. It is markedly calciphilous, but probably not always so (Polunin 1940). It is often badly smutted with fungus.

"Kobresia simpliciuscula s.s. does not reach the Arctic in mainland Europe and is also absent from Iceland. All Svalbard and all studied Greenland and Canada material belong to the 'holarctica' entity, which seems to be the only one in the Arctic" (Elven et al. 2003).

Illustrations. • Herbarium specimen. Plant approximately 15 cm high, with multispicate inflorescence. Nunavut, Devon Island, SE side of Crocker Bay. 25 August, 1999. Reidar Elven. CAN 583232. • Close-up of inflorescence at anthesis. Spikelets at anthesis. Lowermost spikelet with perigynium swollen with black smut. Nunavut, Baffin Island, Ogac Lake, occasional on black seepage slopes with Scirpus caespitosus and Saxifraga aizoides. 5 August, 1965. A.I. McLaren 77. CAN 302047. • Close-up of branching inflorescence. Multispicate inflorescence with distinct branching at the base and with anthers visible. Nunavut, Baffin Island, Kimmirut. M.O. Malte 120282. CAN 28771. • Close-up of mature inflorescence. Mature inflorescence branching at the base. Three stigmas per achene. Nunavut, Baffin Island, Ogac Lake, occasional on black seepage slopes with Scirpus caespitosus and Saxifraga aizoides. 5 August, 1965. A.I. McLaren 77. CAN 302047. • 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.

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