Cyperaceae A. L. de Jussieu
Sedge family.
Plants herbs; perennial herbs. Plants caespitose, or not caespitose. Plants with single unbranched stems, or with unbranched stems in loose clusters, or with erect unbranched stems arising close together, or with branched or unbranched matted stems; less than 15 cm high, or more than 15 cm high; not vegetatively proliferating by bulbils; without milky juice; not glandular viscid. Taproot absent. Roots colourless, or yellow (tomentose), or pallid-brown, or red-brown, or black. Ground level or underground stems horizontal, or not developed horizontally or vertically; rhizomatous, or stoloniferous; elongate, or compact. Scales present, or absent. Aerial stems erect, or decumbent; not conspicuously jointed; filiform, or not filiform; triangular in cross section, or circular or oval in cross section; glabrous, or sparsely hairy, or scabrous. Branches not glaucous; epidermis not flaky. Leaves mostly basal, or distributed along the stems; not distinctly distichous; simple; not heterophyllous; deciduous. Stipules absent. Petioles absent. Sheaths collar absent, or collar 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; with the margins fused to the apex; glabrous. Ligules present; membranous; glabrous; ovate-oblong, or transversely oblong; apices acute, or obtuse; entire. Blades appressed to the stem, or spreading from the vertical; herbaceous; straight, or somewhat curled; linear; without auricles; circular in cross section, or triangular in cross section, or flat, or bristle-like, or strongly keeled, or involute, or revolute, or folded, or caniculate; with parallel veins; midvein conspicuously larger than the lateral veins, or midvein similar in size to other veins in the leaf; septate nodulose, or not septate nodulose; glabrous, or scabrous, or hairy. Blades adaxial surface dull; glabrous. Leaves not lobed. Leaf margins entire; scabrous, or glabrous. Conspicuous hydathodes absent. Leaf apices acuminate.
Forming flowers and fruit. Plants monoecious, or dioecious, or bisexual. 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 of the peduncle; uppermost leaf arising below the middle of the stem, or arising above the middle of the stem; glabrous. Flowering culm nodes not rooting at the lower nodes; not exposed. Flag leaf sheaths not inflated. Leaf or reduced bract closely associated with 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; with sheath longer than the blade, or with sheath shorter than the blade, or sheathless; persistent; without calloused tip. Flowers in inflorescences. Inflorescence spicate, or head-like; terminal; dense; linear, or oblong, or lanceolate, or ovate, or globose or subglobose, or obovate; without bulbils. Pedicels smooth, or scabrous. Inflorescence a single spike, or multispicate; lateral spikes sessile, or lateral spikes borne on pedicels. 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 wholly staminate, or staminate at the apex, or with both sexes in each floret, or pistillate. Cladoprophyll present at the base of the peduncle of lateral spikes, or absent. Inflorescence without involucral bracts. Flowers small, less than 5 mm in diameter or length; sessile or subsessile; bisexual; actinomorphic. Staminate flowers inconspicuous, or conspicuous. 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, or pale grey; with margins the same colour as the body of the scale, or with margins, and sometimes mid-vein 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 scale; reflexed, or not reflexed; obtuse, or cuspidate, or acute; falling early, or not falling early; glabrous, or hairy all over. Floral bracts ovate, or lanceolate, or obovate. Callus not differentiated. Perianth absent, or represented by bristles; bristles silky white, or translucent, or dull white or yellowish, or inconspicuous. Calyx present. Stamens filaments all equal in length; free of the corolla. Nectaries in bisexual flowers absent. Carpels syncarpous. Styles present. Styles base an enlarged bulge, separated from the top of the achene, or base not enlarged, continuous with the achene (Eleocharis). Styles thick and short, or slender, not extending beyond the beak, or slender, extending beyond the beak, or long and thick. Placentation axile. 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 subglobose, or lanceolate, or broadly ovate, or obovate, or elliptic; contracted at the base into a stipe-like structure, or sessile; 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 nerved, or faintly nerved, or appearing nerveless; 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. Fruit without calyx persisting; an achene; glabrous. Legume valves straight. Styles style may persist until dehiscence but is not modified.
Distribution. Northern hemisphere: Canada.
Notes. Represented in the Canadian Arctic Archipelago by 5 genera, Carex, Eleocharis, Eliophorum, Kobresia, and Trichophorum.
Miscellaneous. Species in world 1500, genera in world 120. Genera in study region: Carex, Eleocharis, Eriophorum, Kobresia, Scirpus.
Classification. Subclass Monocotyledonae. Dahlgren’s Superorder Commeliniflorae, Order Cyperales.
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).