Kobresia sibirica (Turcz. ex Ledeb.) Boeck.
Linnaea, 39: 7. 1875.
Kobresia arctica A.E. Porsild
Kobresia hyperborea A.E. Porsild
Kobresia macrocarpa Clokey
Plants caespitose (tightly). Plants more than 15 cm high; (5–)15–30(–40) cm high. Roots pallid-brown, or black. Ground level or underground stems not developed horizontally or vertically. Scales absent. Aerial stems erect; not filiform (0.7–1.3 mm in diameter); circular or oval in cross section; glabrous. Leaves mostly basal. Sheaths greyish brown, or reddish (orange). Ligules present; 0.3–0.4 mm long. Blades straight; linear; circular in cross section, or caniculate (cuneate, with a distinct midvein); glabrous. Blades adaxial surface glabrous.
Plants monoecious. Flowering stems about as high as the leaves (or slightly taller). Leaf or reduced bract closely associated with the base of the inflorescence absent. Inflorescence spicate; oblong, or ovate; 1–2 cm long; 4–8 mm wide; multispicate (compact; composed of 8–20 tiny spike-like panicles "spikelets"; the terminal spikelets with 1 male flower, the lateral spikelets with 1–2 male flowers above, 1 female flower below, and 1–3 sterile scales). Individual spike(s) erect. Terminal spike staminate at the apex. Staminate flowers inconspicuous. Floral scales orange brown; with margins, and sometimes mid-vein paler in colour than the adjacent area of the scale, or with margins paler than body of 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. Perianth absent. Anthers (2–)2.2–2.7(–3) mm long. Styles long and thick (black and longer than the floral scales); 1. Stigmas per style 3. Fruit surrounded by a perigynium. Perigynia open on one side; broadly ovate; 3.5–5.5 mm long; 1.4–1.8 mm wide; sessile; erect or ascending; brown; surface dull; glabrous; faintly nerved (with fine veins); apices without a beak. Fruit an achene (ovoid); 2.8–3.2 mm long; straw coloured. Achenes not filling the upper part of the perigynia; lenticular (oval).
Chromosome information. 2n = 58.
Distribution. North American (western). Low arctic. Range in the Canadian Arctic Archipelago limited. Rare. Arctic Islands: Victoria.
Ecology and habitat. Substrate lake shores, tundra; dry; peat, or with low organic content.
Notes. A local and variable species, not yet fully understood. Some authors consider K. hyperborea and K. macrocarpa to be a distinct endemic North American species, while others include these and K. siberica 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 with an accumulation of dead sheaths at the base and ovate inflorescences. Victoria Island. CAN 127531. • Close-up of inflorescence. Note the ovate shape of the inflorescence compared to that of Kobresia myosuroides. CAN 127531. • Type specimen. Type specimen of Kobresia arctica A.E. Porsild, N.W.T., Mackenzie River, Kittigazuit Island, 69 22'N; 133 46'W, A.E. and R.T. Porsild, 2318, 19–20 July, 1927. CAN 28737. • Arctic Island distribution.
Cite this publication as: Aiken, S.G., Boles, R.L., and Dallwitz, M.J. 1999 onwards. ‘Cyperaceae of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval.’ Version: 6th November 2000. http://http://www.mun.ca/biology/delta/arcticf/. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).
