Carex scirpoidea Michx.
Fl. Bor.-Amer. 2: 171. 1803.
Nomenclatural section used by Flora of North America project subgenus Carex, sect. Scirpinae (Tuckerm.) Kükenthal
Carex athabascensis F.J. Herm.
Carex scirpiformis Mackenzie
Carex scirpoidea var. convoluta Kükenthal
Carex scirpoidea var. scirpiformis (Mackenzie) O’Neill & Duman
Carex scirpoidea var. stenochlaena Holm
Carex stenochlaena (Holm) Mackenzie
Plants not caespitose (but in loose clusters). Plants less than 15 cm high, or more than 15 cm high; (4–)8–20(–30) cm high. Roots pallid-brown. Ground level or underground stems horizontal (that are stout); rhizomatous, or stoloniferous; compact. Scales present (black, brown, red or reddish purple, sometimes obscured by dead material). Aerial stems erect; not filiform (0.3–0.8 mm in diameter); triangular in cross section (sharply so); glabrous. Leaves mostly basal. Sheaths green (or translucent). Ligules present. Blades straight; linear; circular in cross section, or flat (loosely rolled); glabrous, or hairy (margins and midvein minutely scaberulous).
Plants dioecious. Flowering stems about as high as the leaves, or conspicuously taller than the leaves (usually). Leaf or reduced bract closely associated with 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; 0.4–3.5(–6) cm long; with sheath shorter than the blade. Inflorescence spicate; linear, or oblong, or ovate, or globose or subglobose; 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); a single spike. Individual spike(s) erect. Terminal spike wholly staminate (for male inflorescence). Cladoprophyll present at the base of the peduncle of lateral spikes. Staminate flowers conspicuous. Floral scales shorter than the perigynium in fruit; brown, or black; with margins, and sometimes mid-vein paler in colour than the adjacent area of the scale (a narrow, translucent zone); obtuse; 2–3 mm long; 1–1.5 mm wide; hairy all over. Floral bracts hairs very dense. Perianth absent. Anthers 2–3 mm long. Styles slender, extending beyond the beak. Stigmas per style 3. 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 mm wide; sessile; erect or ascending; brown (at the apex), or green (at the base); surface dull; scabrous (with prominent reddish brown, or translucent hairs); appearing nerveless; with 2 keels; apices beaked with a short beak; apex not bidentate. Achenes filling the perigynia; trigonous.
Chromosome information. 2n = 62 and 64.
Distribution. North American. Arctic. Range in the Canadian Arctic Archipelago wide-spread. Common. Arctic Islands: Baffin, Devon, and Ellesmere (new records since Porsild (1957)), Banks, Victoria, King William, Southampton, and Coats.
Ecology and habitat. Substrate wet meadows (less commonly), along streams, river terraces (older and raised), lake shores (on beach ridges), tundra, slopes, sea shore (on rocky sites under the influence of sea spray); dry, or imperfectly drained (less commonly); calcareous, or halophytic (occasionally); rock (sometimes on carbonate plates or cobble), gravel, sand, till, moss; peat, or with low organic content. Although this species can be found in damp places with Sphagnum or Equisetum arvense, it is more commonly found in dry tundra with Dryas integrifolium, Epilobium latifolium, Oxytropis maydelliana and Carex bigelowii subsp. bigelowii, or Poa glauca. On beach ridges, it can be found with Saxifraga tricuspidata.
Notes. Polunin (1940) that this species varies greatly in stature from 5–30 cm, in shape of he spike (which may be subglobose), and 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 recognized 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).
In a study of the response of vegetation to simulated grazing and browsing of vegetation available to caribou in the arctic, Ouellet and Boutin (1994) found that nitrogen, magnesium, potassium and phosphorus levels in regrowth were above the maximum obtained from controls at any point during the growing season and suggested that these changes possibly enhance the quality of these plants as food for herbivores.
In a study of scale-dependent correlation's 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 from low temperatures.
Illustrations. • Herbarium specimen. Upper left hand plant staminate, lower plants pistillate. Note horizontal stems and stem scales. CAN 518224. • Plants in habitat. Male plants with white unispicate inflorescences. Nunavut, Baffin Island, Iqaluit. Susan Aiken 97–022, CAN. Scale bar in cm. • Close-up of plants. Close-up of male plants from the previous image. Nunavut, Baffin Island, Iqaluit. Susan Aiken 97–022, CAN. Scale bar = 1 cm. • Close-up of inflorescence. Close-up of male spike from previous image. Nunavut, Baffin Island, Iqaluit. Susan Aiken 97–022, CAN. • Close-up of staminate inflorescence. Staminate inflorescence approximately 1 cm high. Collected Nunavut, Baffin Island, Iqaluit, August, 1997. Aiken 97–049, CAN. • Close-up of pistillate inflorescence. Pistillate inflorescence approximately 1 cm high. Pistillate scales with margins and midvein lighter in color than the adjacent area. • 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).
