Flora of the Canadian Arctic Archipelago


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

Carex scirpoidea Michx.

English: Scirpus sedge,

French: Carex faux-scirpe,

Inuktitut: Iviit, ivisuka, ivitsuskaka.

Cyperaceae, Sedge family.

Published in Fl. Bor.-Amer. 2: 171. 1803.

Type: Described from Canada: Hudson Bay area. Holotype: P.

Synonymy. Carex scirpoidea Michx. var. stenochlaena Holm, Amer. J. Sci. 168: 20. 1904.

Carex scirpoidea Michx. subsp. stenochlaena (Holm) Á. Löve and D. Löve, Taxon 13: 202. 1964.

Carex scirpiformis Mackenzie, Bull. Torrey Bot. Club 35: 270. 1908.

Carex stenochlaena (Holm) Mackenzie, Bull. Torrey Bot. Club. 35: 269. 1908.

Carex athabascensis F.J. Herm. Leafl. West Bot. 8: 111. 1947.

Vegetative morphology. Plants (4–)8–20(–40) cm high; perennial herbs; caespitose; loosely tufted in several tufts (with scaly black rhizomes). Only fibrous roots present. Roots pallid-brown. Ground level or underground stems horizontal (stout); rhizomatous, or stoloniferous; elongate, or compact. Ground level or underground stems scales present (black, brown, red or reddish purple, sometimes obscured by dead material). Aerial stems erect, or ascending (lax); not filiform (0.3–0.8 mm in diameter). Leaves present; mainly basal; alternate; dying annually and non-persistent (previous season's dead leaves usually absent). Petioles absent. Sheaths present; breaking down into fibres (slowly); not forming a conspicuous build-up at the base of the plant (sheath fronts membranous); green (or translucent); with trichomes (perberulent); sheath collars absent. Ligules present (rounded or acute). Ligule apices acute, or obtuse. Leaves grass-like. Blades 30–120 mm long, 1.5–3(–4) mm wide (widest leaves of the pistilate culms), straight, linear, flat or involute (loosely rolled), veins parallel. Blade adaxial surface glabrous or scabrous (midvein minutely scaberulous). Blade margins scabrous (minutely scaberulous).

Reproductive morphology. Plants dioecious. Flowering stems triangular in cross section (sharply so). Flowering stems about as high as the leaves, or conspicuously taller than the leaves (usually); with leaves, or without leaves. Leaf or reduced bract subtending the base of the inflorescence present, or absent; conspicuous and leaf-like, or reduced, or scale-like (if applicable); shorter than the apex of the inflorescence; 4–35(–60) mm long; persistent; with sheath shorter than the blade. Inflorescences spicate (a single spike usually, very rarely with a short lateral spike of the same sex); linear (or ellipsoid); 0.9–1.2 cm long (staminate), or 0.8–2(–3) cm long (pistillate); 3.5–6(–12) mm wide (staminate spikes), or 2.5–4 mm wide (pistillate spikes). Cladoprophylls present. Inflorescence unispicate. Individual spike(s) erect. Terminal spike completely staminate (for male inflorescence), or pistillate (female inflorescence). Floral scales shorter than the perigynium in fruit, or as long as the perigynium in fruit, or longer than the perigynium in fruit; brown, or black (red or purple tinged); with margins and sometimes midvein paler in colour than the adjacent area of the scale (a narrow, translucent zone; central midrib extending midway to the apex); ovate, or lanceolate; 2–3.5 mm long; 1–1.5 mm wide; hairy all over; apex obtuse. Floral bracts hairy all over; hairs very dense. Flowers unisexual. Staminate flowers conspicuous. Perianth represented by a perigynium. Stamens present (staminate flowers), or absent (pistillate flowers); 3. Anthers 2–3 mm long. Ovary superior; carpels 3; syncarpous. Perigynia sessile. Styles 3; partially fused; slender, 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; broadly ovate; 2.5–3.2 mm long; 1–1.2(–1.6) mm wide (less than or equal to 2.5 times as long as wide); erect or ascending; brown (reddish at the apex), or green (at the base); membranous; surface dull; hairy (with prominent reddish brown, or translucent hairs); appearing veinless; with 2 keels; apices beaked with a short beak (0.1 mm long, orifice circular); apex not bidentate or oblique. Fruit sessile; dry; an achene; indehiscent. Achenes trigonous (1–2 × 0.6–1.2 mm); filling the perigynia (to the full width and at least three-quarters of the length). Seeds 1.

Chromosome information. 2n = 62–64 and 68.

2n = 62–64 and 68.

2n = 62. Jørgensen et al. (1958, Greenland); Löve and Löve (1964b, 1965, 1966b, northeastern USA); Löve (1981d, central Canada); Löve and Ritchie (1966, central Canada); Löve and Ritchie (1966, central Canada); Taylor and Mulligan (1968, western Canada); Zhukova and Petrovsky (1971, Wrangel Island); Engelskjøn and Knaben (1971, northern Norway); Zhukova and Tikhonova (1971, Chukotka); Yurtsev and Zhukova (1978, eastern Chukotka); Petrovsky and Zhukova (1978); Zhukova (1980, southern Chukotka; 1982, northeastern Asia); Dalgaard (1989, western Greenland);

2n = about 62. Johnson and Packer (1968, northwestern Alaska);

2n = 64. Moore and Calder (1964, western Canada);

2n = 68. Heilborn (1939).

Ecology and habitat. Substrates: wet meadows (less commonly), along streams, river terraces (older and raised), lakeshores (on beach ridges), tundra, slopes, seashores (on rocky sites under the influence of sea spray); dry, imperfectly drained moist areas (less commonly); rocks (sometimes on carbonate plates or cobble), gravel, sand, till, moss; peat, with low organic content; calcareous, or halophytic (occasionally). Although this species can be found in damp places with Sphagnum or Equisetum arvense, it is more commonly found in dry tundra with Dryas integrifolia, Chamerion (Epilobium) latifolium, Oxytropis maydelliana and Carex bigelowii subsp. bigelowii, or Poa glauca. On beach ridges, it can be found with Saxifraga tricuspidata.

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. Arctic islands: Baffin, Devon, and Ellesmere (new records since Porsild (1957)), Banks, Victoria, King William, Southampton, and Coats (Digges Island and Melville Peninsula).

Northern hemisphere distribution. Amphi-Atlantic, or amphi-Beringian (broadly), or North American. Yana–Kolyma, 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) indicated that this species varies greatly in height, from 5 to 30 cm, in the shape of the spike (which may be subglobose to elongate), and in the presence or absence of a cauline leaf (which may be as much as 6 cm long and overtop the spike). He noted that while several forms and varieties had been recognised they were so inconsistent as to be not worth taking up.

There has been a significant range extension north to Ellesmere Island since Porsild (1957).

Ouellet and Boutin (1994), in a study of the response of vegetation to simulated grazing and browsing of plants available to caribou in the arctic, found that nitrogen, magnesium, potassium, and phosphorus levels in re-growth plants were above the maximum obtained from ungrazed control plants at any point during the growing season and suggested that grazing changes possibly enhance the quality of these plants as food for herbivores.

In a study of scale-dependent correlations of Arctic vegetation and snow cover in southeastern Victoria Island, Schaefer and Messier (1995) found that C. scirpoidea exhibited positive associations with various measures of snow cover. It is thought that snow cover may reduce the rate of desiccation, protect plants from abrasion, and insulate them from low temperatures.

Carex scirpoidea was found to be an early coloniser of oil spills in Alaska (Kershaw and Kershaw 1986).

Dunlop (2002), in the Flora of North America treatment, recognises four races as subspecies. The one occurring in the Arctic Archipelago is subsp. scirpoidea, which is recognised by "the lack of persistent leaf bases on the flowering shoots, ovate perigynia that are tightly enveloped by the perigynia on all sides, and leaves widely V-shaped in transverse section." (p. 551). It is widespread from the Russian Far East throughout North America and Greenland to northern Norway. He also recognised three others as segregates within the range of subsp. scirpoidea. One of these, the Cordilleran subsp. stenochlaena, reaches the Arctic in northwestern North America and is perhaps the most common race there.

Illustrations. • Herbarium specimen. Upper left-hand plant staminate, lower plants pistillate. Note horizontal stems. CAN 518224. • Habitat: Cape Dorset. Female plants growing on dry tundra with heather. Male plants, not shown here, common in the area. Nunavut, Baffin Island, Cape Dorset. 3 August, 2005. Aiken. No voucher. • Female plants in habitat. Female plants have blackish unispicate inflorescences with white stigmas protruding. Nunavut, Baffin Island, Iqaluit. 6 July, 2004. Aiken and LeBlanc 04–019. CAN. • Male plants in habitat. Male plants with white unispicate inflorescences 0.9–1.2 long. Nunavut, Baffin Island, Iqaluit. Aiken 97–022. CAN. Scale bar in cm. • Close-up of isolated male plant. Loosely tufted plant with unispicate, staminate inflorescence barely taller than the leaves. This flowering plant growing in a cryptogamic mat. Most other plants on the very dry hillside nearby not flowering. Nunavut, Baffin Island, Ogac Lake. 7 July, 2004. Aiken and LeBlanc 04–045. CAN 586514. • Close-up of staminate inflorescence. Close-up of male spike, approximately 1 cm long. Note the prominent exposed anthers. Nunavut, Baffin Island, Iqaluit. Aiken 97–022. CAN. • Close-up of staminate inflorescence. Post-anthesis male inflorescence approximately 1 cm long. Nunavut, Baffin Island, Iqaluit. August, 1997. Aiken 97–049. CAN. • Close-up of pistillate spikes. Female plants with single pistillate spikes and black scales. Stigmas per floret 3. Nunavut, Baffin Island, Iqaluit. 6 July, 2004. Aiken and LeBlanc 04–019. CAN. • Close-up of single receptive pistillate spike. Single pistillate spike with black scales and 3 white receptive stigmas per floret. Nunavut, Baffin Island, Iqaluit. 6 July, 2004. Aiken and LeBlanc 04–019. CAN 586492. • Close-up of pistillate spike. Portion of pistillate spike showing smooth black floral scales. Perigynia with long beaks and surfaces covered in fuzzy hairs. 2 August, 1986. Aiken, Campbell and Robinson 86–497. 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.