Carex L.
Sedge.
Cyperaceae, sedge family.
Syst. ed. 1. 1735.
Vegetative morphology. Plants herbs; perennial herbs; 2–30(–90) cm high; caespitose, or not caespitose; monoecious or rarely dioecious grass-like plants with solid, often triangular stems caespitose, loosely tufted or matted. Roots yellow (tomentose), or pallid-brown (most often), or red-brown, or black. Ground-level or under-ground 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 in a basal tuft, or distributed along the stems; existing for a single season or less. Petioles absent. Sheaths 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 (purple e.g. C. scirpoidea); collars absent. Ligules present; 0.1–1 mm long (the ligule flap; to 10 mm long when the shape of the insertion is measured). Blades 10–250(–440) mm long; 0.2–6.3 mm wide. 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; veins parallel; septate nodulose (rarely), or not septate nodulose. Blade margins entire; scabrous (scaberulous at the tip), or glabrous.
Reproductive morphology. Plants monoecious, or dioecious. Flowering stems present. Flowering stems shorter than the leaves, or about as high as the leaves, or conspicuously taller than the leaves; with leaves (associated with lateral spikes when these are present), or without leaves in the upper half (if the inflorescence is a solitary spike); glabrous. 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; 10–190 mm long; with sheath longer than the blade, or with sheath shorter than the blade, or sheathless; persistent. 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 glabrous, 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 (Subgenus Carex), or absent (Subgenus 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 midvein 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). Floral bracts ovate, or lanceolate. Perianth absent. Flowers unisexual. Stamens 3. Anthers 0.8–4.1 mm long. Carpels syncarpous. 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. Placentation basal. 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; membranous; 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 or oblique. Fruit an achene. 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, pastures, prairies, tundra, and the herb layer of temperate forests.
World wide, there may be as many as 2000 species. Carex is one of the
largest genera in the eastern Canadian flora with approximately 300 species and
the largest genus in the eastern Canadian Arctic Archipelago flora, with 30
species.
Kükenthal (1909) in the only world wide 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.
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 that bears staminate flowers in the
perigynium of Kobresia. (GoethebEurope,1998, Peter Ball personal
communication 1999).
Illustrations. • Carex mackenziei. Habitat. Circular colony of Carex mackenziei, dying out in the middle, in a brackish depression in a salt marsh. Norway: Nordland, Beiarn, Beiarosen. July 1984. Photographed by H.Edvardsen. • Carex mackenziei. Stand. Profusely fertile stand in depression in brackish marsh. The species is a specialist of brackish depressions with stagnant waters and anaerobic conditions. Norway: Troms, Lenvik. June 1977. Photographed by R.Elven. • Carex mackenziei. Close-up. Vegetative and fertile shoots. Norway: Finnmark, Porsanger. July 1983. Photographed by R.Elven.
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, L.J. Gillespie, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, A.K. Brysting and H. Solstad. 1999 onwards. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).
