Carex (Dill.) L.
Syst. ed. 1. 1735.
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; 2–30(–90) cm high. Roots yellow (tomentose), or pallid-brown (most often), 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; filiform, or not filiform; triangular in cross section, or circular or oval in cross section; glabrous (usually), or sparsely hairy, or scabrous. Leaves mostly basal, or distributed along the stems. Sheaths greyish brown, or brown, or green, or reddish (purple e.g. C. scirpoidea). Ligules present; 0.1–1 mm long (the ligule flap; to 10 mm long when the shape of the insertion is measured). Blades straight, or somewhat curled; linear; 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; septate nodulose (rarely), or not septate nodulose; glabrous, or scabrous (often scabrous and only at the tip).
Flowering stems shorter than the leaves, or about as high as the leaves, or conspicuously taller than the leaves. 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; 0.1–19 cm long; with sheath longer than the blade, or with sheath shorter than the blade, or sheathless. Inflorescence spicate, or head-like; dense, or diffuse; linear, or oblong, or lanceolate, or ovate, or globose or subglobose, or obovate; 0.4–15(–20) cm long; 1.5–15(–50) mm wide. Pedicels smooth, or scabrous. Inflorescence a single spike, or multispicate; 1–8 spikes; lateral spikes sessile, or lateral spikes borne on pedicels. Individual spike(s) erect, or ascending, or divergent, or pendent. Terminal spike staminate at the base, or wholly staminate, or staminate at the apex, or pistillate (rarely). Cladoprophyll present at the base of the peduncle of lateral spikes (Carex), or absent (Vignea). 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 (rarely); brown, or black, or pale grey, or orange brown, or green; 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; reflexed (rarely), or not reflexed; obtuse, or cuspidate, or acute; falling early, or not falling early (usually); 1–5.5 mm long; 0.7–3.2 mm wide; glabrous, or hairy all over (rarely). Perianth absent. Anthers 0.8–4.1 mm long. Styles thick and short, or slender, not extending beyond the beak, or slender, extending beyond the beak, or long and thick (rarely). Stigmas per style 2–3. Fruit surrounded by a perigynium (an inflated sac surrounding the ovary), or not surrounded by a perigynium. Perigynia 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; 1.5–6 mm long; 0.5–3 mm wide; contracted at the base into a stipe-like structure, or sessile; erect or ascending, or reflexed (rarely), or spreading at maturity; black, or straw-coloured, or golden brown, or brown, or green, or whitish; surface glossy, or surface dull; glabrous, or hairy (rarely), or scabrous; tuberculate, or papillose; strongly nerved, or faintly nerved, or appearing nerveless; inflated (rarely), or not inflated; not keeled, or with 2 keels, or with 3 keels (rarely); 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. Achenes filling the perigynia, or not filling the upper part of the perigynia; lenticular, or trigonous.
Chromosome information. 2n = 18–80.
Notes. The genus Carex includes the sedges that dominate wetlands, pasture, prairies, tundra and the herb layer of temperate forests. Worldwide, there may be as many as 2000 species. Carex is one of the largest genera in the Canadian flora with approximately 300 species and the largest genus in the Arctic Archipelago flora with 30 species.
Kükenthal (1909) in the only worldwide monograph of the genus divided Carex into four subgenera: (1) Primocarex Kükenthal, characterized by solitary terminal spikes; (2) Vignea (P. Beauv. ex Lestib. f.) Peterm., distinguished by sessile, bisexual inflorescence units, the lack of a cladoprophyll (a tubular structure subtending an inflorescence), and distigmatic flowers; (3) Indocarex Ballon, a mainly tropical group with paniculate inflorescences, bisexual inflorescence units, cladoprophylls, inflorescence prophylls (perigynium-like organs subtending lateral inflorescence units), and tristigmatic flowers; and (4) Carex, distinguished by mostly peduncled, unisexual inflorescence units, cladoprophylls, and usually tristigmatic flowers.
Kükenthal (1909) considered subg. Primocarex primitive within Carex because its spikelets typically have a conspicuous secondary axis (rachilla). Most subsequent authors (e.g. Reznichek 1990) have criticized this, believing the species in subg. Primocarex to have evolved independently from multispicate species in the other subgenera. Most recent authors recognize three subgenera (Carex, Indocarex and Vignea) with members of Primocarex divided between subg. Vignea or Carex, but contrasting opinions have been expressed (Starr et al. 1999).
Crins (1990) discussed phylogenetic considerations in the genus Carex below the sectional level. Starr et al. 1999 inferred the phylogenetic position of Carex section Phyllostyctachys and its implications for phylogeny and subgeneric circumscription in Carex from sequences of the ITS (internal transcribed spacer) region of nrDNA. Phylogenetic reconstruction identified two main clades: (1) a "compound" clade composed of sections from subg. Indocarex Primocarex, and a portion of subg. Carex, and (2) a "reduced" clade consisting of sections from subg. Carex (Phyllostachys and Primocarex (Filifoliae and Firmiculmes). Subgenus Indocarex was paraphyletic within the "compound" clade supporting classifications that have merged it within a wider subg. Indocarex/Carex/Primocarex line. Subgenus Primocarex was polyphyletic. This result was consistent with theories that extreme reduction has occurred along several different evolutionary lines in Carex.. Phylogenetic theories inferred from the presence or abnormal growth of the rachilla where not supported by tree topologies. Difficult sectional circumscriptions, such as the separation of sections Laxiflorae and Careyanae, were strongly upheld by sequence data. Starr et al. (1999) concluded that the ITS region is an effective tool for defining sectional limits and for estimating relationships among sections in Carex but does not provide enough phylogenetic information to fully resolve relationships below the sectional level.
Sectional sequence proposed by the Flora of North America project:
subgenus Vignea (P. Beauv. ex Lestib. fil.) Peterm.
sect. Chordorrhiza (Fries) Mackenzie C. chordorrhiza Ehrh.
sect. Physoglochin Dumortier (1827). C. gynocrates Wormsk. ex Drej.
sect. Foetidae (=sect. Dioicae) (L.H. Bailey) Kükenthal C. maritima Gunn.
sect. Glareosae G. Don (1830) (=sect. Heleonastes), C. lachenalii Schkuhr, C. glareosa Wahlenb., C. marina Dewey, C. ursina Dewey
sect. Ovales Kunth (1837). This name is predated by sect. Cyperoideae G. Don. (1830), but Flora Europaea separates the sections. C. macloviana d’Urv.
subgenus Carex
sect. Phacocystis Dumortier (1827). (= Acutae + Cryptocarpae) C. aquatilis Wahlenb. var. stans (Drej.) Boott, C. bigelowii Torr. ex. Schwein., C. lugens Holm, C. subspathacea Wormsk. ex Hornem.,C. rufina Drej.
sect. Atratae Christ (1885). C. holostoma Drej., C. norvegica Retz.
sect. Limosae (O.F. Lang) Kükenthal C. rariflora (Wahlenb.) Sm.
sect. Racemosae G. Don (1830) = (Bicolores). C. bicolor All.
sect. Paniceae G. Don (1830). C. vaginata Tausch
sect. Hymenochlaenae Bailey (1886) = Gracillimae + Sylvaticae + Longirostres, + Capillares. C. capillaris L., C. williamsii Britt.
sect. Aulocystis Dumortier (1827) (=Ferruginae). C. atrofusca Schkuhr, C. fuliginosa Schkuhr, C. petricosa Dew.
sect. Vesicariae Carey (1848). C. membranacea Hook. C. saxatilis L. (including C. physocarpa Presl
sect. Leucoglochin Dumortier (1827). (= Orthocerates). C. microglochin Wahlenb.
sect. Scirpinae (Tuckerm.) Kükenthal, C. scirpoidea Michx.
sect. Lamprochlaenae (Drej.) Bailey (1886) (=Obtusatae). C. obtusata Liljeb., C. supina Willd. ex Wahlenb. var. spaniocarpa (Steud.) Boivin
sect. Petreae (O.F. Lang) Kükenthal (=Rupestris). C. glacialis Mackenzie, C. rupestris All.
sect. Nardinae Kükenthal C. nardina
sect. Capitatae Mackenzie C. capitata Sol.
Bernard (1990) reporting on the life history and vegetative reproduction in Carex observed that they are modular organism that reproduce vegetatively by rhizomes or other means, some species forming extensive and long-lived clones, others tufts, clumps, or tussocks of various sizes. Most temperate and Arctic species have shoots formed during the previous year, some emerging in autumn, others remaining below ground until spring.
Anatomical aspects of the taxonomy of sedges where discussed by Standley (1990) who studied the anatomy of achene epidermis and leaves. She suggested that single conical silica bodies and epapillose hypostomatous leaves are primitive character states in Carex, and that as both primitive and derived character states are widely distributed among sections anatomical character should not be generally applied as measure of similarity in phenetic approaches to classification but have potentially major importance in phylogenetic studies within and among sections.
Many species have a relict rachilla that is smaller than the large structure in C. microglochin. It is assumed to be the remains of the branch which bears staminate flowers in the perigynium of Kobresia. (Goethebeur, 1998, Peter Ball personal communication 1999).
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).