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 sibirica (Turcz. ex Ledeb.) Boeck.

Cyperaceae, Sedge family.

Published in Linnaea 39: 7. 1875.

Type: Described from southeastern Siberia: Burjat Republic, Nukhu-Daban plateau.

Synonymy. Elyna sibirica Turcz. ex Ledeb., Fl. Ross. 4: 262. 1852.

Kobresia arctica A.E. Porsild, Sargentia 4: 15. 1943.

Kobresia hyperborea A.E. Porsild, Bull. Natl. Mus. Canada 121: 103. 1951.

?Kobresia macrocarpa Clokey, N. Amer. Fl. 18: 5. 1931.

Vegetative morphology. Plants (5–)15–30(–40) 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 (0.7–1.3 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; greyish brown, or reddish orange (orange, somewhat glossy, bladeless); sheath collars absent (closed). Ligules present; 0.3–0.4 mm long. Leaves grass-like. Blades (20–)50–100(–150) mm long, (0.25–)0.5–1.2(–2) mm wide. Leaves filiform. Blades straight, linear, circular in cross section or channelled (cuneate, with a distinct midvein), 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 circular or oval in cross section. Flowering stems about as high as the leaves (or slightly taller); without leaves. Leaf or reduced bract subtending the base of the inflorescence absent. Inflorescences spicate; oblong, or ovate; 1–2 cm long; 4–8 mm wide. Inflorescence multispicate. Inflorescence 8–20 spikes (tiny spike-like panicles "spikelets"; the terminal spikelets with 1 male flower, the lateral spikelets 1–3 sterile scales, 1 female flower below, and with 1–2 male flowers above, in appearance more like a single spike). Individual spike(s) erect. Terminal spike staminate at the apex. 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 only near the base); obovate (to circular, apex obtuse); (3.5–)4.5–6.5 mm long; 1–3 mm wide; glabrous; apex acute. Staminate flowers inconspicuous. Perianth represented by a perigynium. Stamens 3. Anthers (2–)2.2–2.7(–3) 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; broadly ovate; 3.5–5.5 mm long; 1.4–1.8 mm wide; erect or ascending; brown; membranous; surface dull; glabrous; faintly veined (with fine veins); apices without a beak. Fruit sessile; dry; an achene (ovoid); obovate; straw-coloured; (2.6–)2.8–3.5(–4) mm long; 1–1.4 mm wide; indehiscent. Achenes trigonous; not filling the upper part of the perigynia. Seeds 1.

Chromosome information. 2n = about 54-58-62.

2n = about 54. Johnson and Packer (1968, northwestern Alaska);

2n = 58. Zhukova (1969, northeastern Asia); Löve et al. (1971, western North America); Zhukova and Petrovsky (1971, Wrangel Island);

2n = 62. Zhukova and Petrovsky (1980, western Chukotka).

Ecology and habitat. Substrates: lakeshores, tundra; dry; peat, with low organic content. Growing in rather dry peaty tundra.

North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut. Range in the Canadian Arctic Archipelago limited. Rare. Low Arctic. Arctic islands: Victoria.

Northern hemisphere distribution. Amphi-Beringian, or Siberian. Polar Ural – Novaya Zemlya, Taimyr – Severnaya Zemlya, Anabar–Olenyok, Kharaulakh, West Chukotka, Wrangel Island, South Chukotka, East Chukotka, West Alaska, North Alaska – Yukon, Central Canada.

General notes. A local and variable species, not yet fully understood. Some authors consider K. hyperborea and K. macrocarpa to be distinct endemic North American species, while others include these and K. sibirica in the southwest Asian species K. schoenoides (C.A. Meyer) Steudel. In the Asian plants, the bisexual spikelets are reported to have three staminate flowers and no sterile scales (P. Ball, personal communication, 1998).

Illustrations. • Herbarium specimen. Plants approximately 15 cm high with a dense palisade of dead brown-black sheaths, flowering stems without leaves, and single spicate-like heads ovate to obovate in shape. Nunavut, Victoria Island, Cambridge Bay. 27 July, 1997. L.L. Consaul and L.J. Gilllespie 1127. CAN 582313. • Herbarium specimen. Note palisade of dead orange-brown sheaths and spike-like inflorescence similar to that of K. myosuroides, but larger. Nunavut, Cambridge Bay. 14 August, 1987. S.A. Edlund and G.W. Argus 12688. CAN 526691. • Close-up of inflorescence of previous specimen. Note membranous, translucent floral scales and and dark brown walls of the perigynia that subtend achenes. Achenes have 3 stigmas. Nunavut, Cambridge Bay. 14 August, 1987. S.A. Edlund and G.W. Argus 12688. CAN 526691. • Close-up of mature inflorescence. Mature inflorescence. Perigynium (a) seen through membranous wall. Long beak (b) with three stigmas. Most of the stigmas have broken off the maturing achenes. N.W.T., Great Bear Lake, Cape McDonnel. 2 August, 1928. A.E. and R.T. Porsild 5101. CAN 28732. • Close-up of perigynium. Achene with a long beak (style) that branches into three stigmas and is surrounded by an open perigynium (left and top arrows) and a floral bract (right arrows). Scale bar = 2 mm. N.W.T., Great Bear Lake. 2 August, 1928. A.E. and R.T. Porsild 5101. CAN 28723. • Close-up of inflorescence. Large inflorescence with ovate shape. Kobresia myosuroides inflorescences are smaller and never ovate. Nunavut, Victoria Island, Holman. CAN 127532. • Type specimen. Type specimen of Kobresia arctica A.E. Porsild. N.W.T., Mackenzie River, Kittigazuit Island. 19–20 July, 1927. A.E. and R.T. Porsild 2318. CAN 28737. • 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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