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

Cyperaceae A.L. de Jussieu

French: Cypéracées,

Inuktitut: Iviit, ivisuka, ivitsuskaka.

Cyperaceae, Sedge family.

Vegetative morphology. Plants perennial herbs; caespitose, or not caespitose. Only fibrous roots present. Roots colourless, or yellow (tomentose), or pallid-brown, or red-brown, or black. Ground level or underground stems horizontal, or absent; rhizomatous, or stoloniferous; elongate, or compact. Ground level or underground stems scales present, or absent. Aerial stems erect, or decumbent; filiform, or not filiform. Leaves mainly basal, or distributed along the stems; alternate; dying annually and non-persistent, or marcescent. Petioles absent. Sheaths present; persisting, or breaking down into fibres; forming a conspicuous build-up at the base of the plant, or not forming a conspicuous build-up at the base of the plant; greyish brown, or brown, or green, or reddish orange; with the margins fused to the apex; glabrous; sheath collars absent. Ligules present; membranous; glabrous; ovate-oblong, or transversely oblong. Ligule apices acute, or obtuse; entire. Leaves grass-like. Blades appressed to the stem or spreading, straight or somewhat curled, linear, circular in cross section or flat or bristle-like or strongly keeled or involute or revolute or folded or channelled, veins parallel, midvein conspicuously larger than the lateral veins or midvein similar in size to other veins in the leaf, septate nodulose or not septate nodulose. Blade adaxial surface dull, glabrous. Blade abaxial surface glabrous or scabrous. Blade margins entire, scabrous or glabrous; apices acuminate.

Reproductive morphology. Plants monoecious, or dioecious, or bisexual. Flowering stems triangular in cross section, or circular or oval in cross section. Flowering stems shorter than the leaves, or about as high as the leaves, or conspicuously taller than the leaves; with leaves, or without leaves, or without leaves in the upper half; uppermost leaf arising below the middle of the stem, or uppermost leaf arising above the middle of the stem. Leaf or reduced bract subtending the base of the inflorescence present, or absent; conspicuous and leaf-like, or reduced, or scale-like; exceeding the inflorescence, or similar in length to the inflorescence, or shorter than the apex of the inflorescence; persistent; with sheath longer than the blade, or with sheath shorter than the blade, or sheathless. Inflorescences spicate, or head-like, or a spike of spikes, or a raceme of spikes; dense, or diffuse (when spikes are borne on pedicels); linear, or oblong, or lanceolate, or ovate, or globose or sub-globose, or obovate. Pedicels present (term used to describe branches in a multispicate inflorescence that subtend individual groups of spikes); glabrous, or scabrous. Cladoprophylls present, or absent. Individual spike(s) erect, or ascending, or divergent, or pendent. Bisexual spike(s) with empty bracts at the base, or without empty bracts at the base. Terminal spike staminate at the base, or completely staminate, or staminate at the apex, or with both sexes in each floret, or pistillate. 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, or orange-brown, or green; with margins the same colour as the body of the scale, or with margins and sometimes midvein paler in colour than the adjacent area of the scale, or with margins darker in colour than the midvein, or with margins paler than body of the scale; reflexed, or not reflexed; falling early, or not falling early; glabrous, or hairy all over; apex obtuse, or cuspidate, or acute. Flowers small; unisexual, or bisexual. Staminate flowers inconspicuous, or conspicuous. Perianth represented by bristles (the "cotton" of cotton grasses), or a perigynium. Perianth bristles silky white, or translucent, or dull white, or inconspicuous. Stamens present (staminate flowers), or absent (pistillate flowers); 3. Ovary superior; carpels 3; syncarpous. Perigynia contracted at the base into a stipe, or sessile. Styles 2, or 3; partially fused; thick and short, or slender, not extending beyond the beak, or slender, extending beyond the beak, or long and thick. Stigmas per ovary 2, or 3. Placentation basal. Ovules per ovary 1. Fruit surrounded by a perigynium, or not surrounded by a perigynium. Perigynia open on one side, or with a slit running down the beak on the abaxial side through which the style protrudes, or fused to the apex except for a small aperture through which the style protrudes; globose, or sub-globose, or lanceolate, or broadly ovate, or obovate, or elliptic; erect or ascending, or reflexed, or spreading at maturity; black, or straw-coloured, or golden brown, or brown, or green, or whitish; membranous; surface glossy, or surface dull; glabrous, or hairy, or scabrous; tuberculate, or papillose; strongly veined, or faintly veined, or appearing veinless; inflated, or not inflated; not keeled, or with 2 keels, or with 3 keels; apices beaked with a long beak, or beaked with a short beak, or merely conical or rounded; apex oblique, becoming slightly bidentate, or deeply bidentate, or not bidentate or oblique. Fruit sessile; dry; an achene; ovoid, or obovate, or oblong. Achenes lenticular, or trigonous, or subterete. Seeds 1.


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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