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

Carex membranacea Hooker

English: Membranous sedge, fragile sedge,

French: Carex membraneux,

Inuktitut: Kilirnit ajjkasangir iviit, iviit, ivisuka, ivitsuskaka.

Cyperaceae, Sedge family.

Published in Hooker in C.F. Lyon, An attempt to reach Repulse Bay. 195. 1825.

Type: Canada, Nunavut, Southampton Island, 1821–1823, W.E. Parry. Holotype: K.

Synonymy. Carex hymenocarpa Drejer, Naturhist. Tidsskr. 3: 476. 1840–1841 (illegitimate substitute for C. membranacea Hooker).

Carex membranopacta L. Bailey, Bull. Torrey Bot. Club 20: 428. 1893 (illegitimate substitute for C. membranacea Hooker).

Carex physochlaena Holm, Amer. J. Sci. Arts Ser. IV, 17: 317. 1904.

Vegetative morphology. Plants (10–)15–40(–55) cm high (scabrous distally); perennial herbs; caespitose (loosely clustered). Only fibrous roots present. Roots yellow, or pallid-brown. Ground level or underground stems horizontal; rhizomatous (stout and scaly); elongate. Ground level or underground stems scales present. Aerial stems erect; not filiform (robust 0.5–1.2(-2.1) mm in diameter, above the uppermost leaf). Leaves present; mainly basal (6–12 per stem); alternate; marcescent. Petioles absent. Sheaths present; persisting; not forming a conspicuous build-up at the base of the plant (usually); brown, or reddish orange (tightly enveloping the stem; hyaline ventrally; mouth truncate or concave); sheath collars absent. Ligules present (0.4–3.1(-4.2) mm long, shorter than wide, obtuse at the apex; V-shaped). Leaves grass-like. Blades 50–150(–320) mm long, (1–)2.5–5(–6.2) mm wide (keeled), somewhat curled, linear, flat or revolute (at the margins) or folded (loosely), veins parallel. Blade adaxial surface glabrous or scabrous (minutely scaberulous on the midvein). Blade margins scabrous (minutely scaberulous).

Reproductive morphology. Plants monoecious. Flowering stems triangular in cross section (obtusely). Flowering stems about as high as the leaves, or conspicuously taller than the leaves (usually); with leaves. Leaf or reduced bract subtending the base of the inflorescence present; conspicuous and leaf-like (very variable); exceeding the inflorescence, or similar in length to the inflorescence, or shorter than the apex of the inflorescence; 6–190 mm long; persistent; sheathless. Inflorescences a spike of spikes (pedicels present but short); 2.5–10(–13) cm long (each spike to 1–4.5 cm long); 15–30 mm wide. Pedicels glabrous (or minutely scaberulous, 1–20(-42) mm long). Cladoprophylls present. Inflorescence multispicate. Inflorescence 3–5(–6) spikes. Individual spike(s) ascending. Terminal spike completely staminate (9–29 mm long, 1.8–5.2 mm wide; sometimes 1–3 staminate spikes present). Floral scales shorter than the perigynium in fruit, or as long as the perigynium in fruit; black (purplish), or brown; with margins and sometimes midvein paler in colour than the adjacent area of the scale; ovate; 2.2–4.5(–5.5) mm long; 1–1.7(–3) mm wide; glabrous; apex obtuse, or acute. Flowers unisexual. Staminate flowers conspicuous. Perianth represented by a perigynium. Stamens present (staminate flowers), or absent (pistillate flowers); 3. Anthers 2.1–3.2 mm long. Ovary superior; carpels 3; syncarpous. Perigynia contracted at the base into a stipe (0.2–0.9 mm long). Styles 3; partially fused; thick and short. 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; elliptic (abruptly contracted into a beak at the apex); (2.2–)2.5–3(–4.1) mm long; 1.3–2.2 mm wide; reflexed, or spreading at maturity (crowded, forming angles 80–110° with the spike axis); black, or brown; membranous; surface glossy; glabrous; tuberculate (slightly); faintly veined (veins not running into the beak); inflated (slightly); not keeled; apices beaked with a short beak (0.2–0.8 mm long); apex deeply bidentate (with teeth to 0.3 mm long). Fruit sessile; dry; an achene; indehiscent. Achenes trigonous (yellow, smooth); not filling the upper part of the perigynia. Seeds 1.

Chromosome information. 2n = 74 (76–80).

2n = 74-80.

2n = 74. Zhukova and Petrovsky (1971, Wrangel Island; 1980, western Chukotka); Petrovsky and Zhukova (1978); Zhukova (1980, south Chukotka; 1982, northeastern Asia);

2n = 76. Löve (1981d, northern Canada);

2n = 76–80. Johnson and Packer (1968, northwestern Alaska).

Ecology and habitat. Substrates: wet meadows, hummocks, around the margins of ponds (and in swales), depressions of low-centre polygons, marshes, along streams, river terraces (both lower and raised terraces, and on deltas), lakeshores (in peat bogs), tundra, slopes (rocky), ridges, seashores (on flats and on older beach ridges further inland); imperfectly drained moist areas, seepage slopes; rocks, gravel, sand, silt, clay (occasionally), till; with low organic content, with high organic content, peat; calcareous. Occurs in a variety of moist habitats, particularly sedge meadows. It has been noted both around the margins of wet meadows and in the deeper, more saturated areas. Typical associates are Carex aquatilis var. minor, C. scirpoidea, C. atrofusca, or Eriophorum angustifolium. It has also been reported in substrates of widely ranging organic content, including bare wet sand, humic seepage slopes and peaty areas. It frequently occurs as a dominant in a wide variety of open, moist habitats that often have a well-developed peat layer. It does not usually grow in standing water or in shoreline communities.

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, Ellesmere, and Parry islands (Bathurst, Melville), Cornwallis, Banks, Victoria, Prince of Wales, Somerset, King William, Southampton, and Coats (Prince Charles, Mansel and Resolution Islands and Boothia Peninsula).

Northern hemisphere distribution. Amphi-Beringian, or North American. West Chukotka, Wrangel Island, South Chukotka (?), East Chukotka, West Alaska, North Alaska – Yukon, Central Canada, Labrador – Hudson Bay, Ellesmere Land – Peary Land.

General notes. Ford and Ball (1992, p. 634) noted that this species is "the most restricted of all the short-beaked taxa [in section Vesicariae], being confined primarily to the North American Arctic. It is noticeably absent from Greenland and occurs in Eurasia only in the Chukot Peninsula and Koryakskiy Mountain region of extreme eastern U.S.S.R. [Russia]. It is one of the few truly northern species of sedge, being widespread in the Arctic Archipelago and occurring in the south as far as northern British Columbia, the southern boundary of the Northwest Territories and northern Quebec. Although this species is said to occur in the Churchill, Manitoba region (Johnson 1987, Porsild and Cody 1980)," no specimen has been found to support this suggestion.

Ford and Ball (1992) noted that anatomically C. saxatilis is indistinguishable from C. membranacea and presented evidence to suggest that "this similarity is the result of homoplasy or stasis in anatomical characters rather than an indication of a close evolutionary relationship." (p. 620).

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

Illustrations. • Habitat. Plants growing beside a small pond. Nunavut, Baffin Island, Iqaluit. Aiken 97–008. CAN. • Habitat. Rhizomatous plant between the markers with young multispicate inflorescenses. Nunavut, Baffin Island, Iqaluit. 6 July, 2004. Aiken and LeBlanc 04–015. CAN 586488. • Close-up of plants. Close-up of plant approximately 20 cm high. Nunavut, Baffin Island, Iqaluit. Aiken 97–008. CAN. • Habitat. Isolated plants about 10 cm high growing on a wet seepage slope. Nunavut, Ellesmere Island, Franklin Pierce Bay, 7926'N, 7538'W. Aiken 98–032. CAN. Photograph by Mollie MacCormac. Scale bar in cm. • Close-up of young inflorescence. Note leaf-like bract subtending the inflorescence is closely associated with the lower-most pistillate spike. Terminal spikes staminate. Aiken and LeBlanc 04–015. CAN 586488. • Close-up of pistillate spike. Young pistillate spike with brownish black ovate floral scales and three stigmas per perigynium. Aiken and LeBlanc 04–015. CAN 586488. • Close-up of staminate spike. Terminal spike staminate with three anthers per floret. Below, pistillate spike with three stigmas per floret. Nunavut, Baffin Island. August, 2005. Aiken 05–088. CAN 586959. • Close-up of inflorescence. Multispicate inflorescence with terminal male spike and two pistillate spikes. Nunavut, Baffin Island, Iqaluit. Aiken 97–008. CAN. • Close-up of inflorescence. Multispicate inflorescence with two staminate spikes and one mature pistillate spike with shiny purplish black perigynia. Nunavut, Baffin Island, Iqaluit. Aiken 97–008. 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.

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