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Aquatic and Wetland Vascular Plants of the Northern Great Plains

Carex L. -- Sedge

Monoecious or rarely dioecious, cespitose or rhizomatous, grasslike perennials; culms simple, acutely to obtusely trigonous, exceeding or shorter than the leaves. Leaves grasslike, the blades flat to involute; sheaths hyaline or cross-rugulose ventrally, hyaline, green-and-white mottled or septate-nodulose dorsally. Inflorescence terminal, headlike, dense to open, usually consisting of few to many spikes, or less often of a single spike, the spikes usually subtended by leaflike bracts, the lowermost bracts best developed, sometimes much reduced; spikes unisexual (Fig. 135a), or bisexual (Fig. 135b), when bisexual, the spikes either androgynous (with the staminate flowers above the pistillate) or gynaecandrous (with the pistillate flowers above the staminate). Flowers unisexual, each subtended by a scale; perianth none; male flowers composed of 3 stamens; female flowers composed of a single ovary contained within a saclike perigynium (Fig. 135c); perigynia trigonous to plano-convex, lanceolate to ovate or suborbicular, strongly beaked to beakless, variously nerved, often winged on the margins when plano-convex, sometimes spongy-thickened at the base; beak, when present, entire, obliquely cut or bidentate at the apex; styles bifid or trifid (stigmas 2 or 3), the branches protruding from the beak or tip of the perigynium. Achenes developing within the perigynium, lenticular or trigonous, the style jointed with the achene or continuous with it.

The largest genus of vascular plants in N.Amer.; most spp. characteristic of wet habitats.


Hermann, F. J.  1970.  Manual of carices of the Rocky Mountains and Colorado 
     Basin.  U.S.D.A. Forest Serv. Handbook No. 374, Washington, D.C.

Kolstad, O. A. 1966. The genus Carex of the High Plains, Prairie Plains 
     and associated woodlands in Kansas, Nebraska, South and North Dakota.  
     Unpubl. Ph.D. thesis, Univ. Kans., Lawrence.

Wheeler, G.  1981.  A study of the genus Carex in Minnesota (Volumes I
	and II).  Unpubl. Ph.D. thesis, Univ. Minn., St. Paul.

Lead Characteristic Go To
1 Spikes only one per culm, terminal, continuous, no lateral spikes present. (Those with 2 or more spikes aggregated in a dense spike like head will key in the next section, as will those with 1- to few-flowered lateral spikes.) Lead 2
1 Spikes 2 or more per culm, densely crowded in a spikelike head to widely separated, the lateral spikes occasionally only 1- to few-flowered. Lead 3
2 Plants tufted; stigmas 3. C. leptalea
2 Plants rhizomatous; stigmas 2. C. gynocrates
3 Spikes mostly unisexual, the terminal ones usually staminate, the lower ones mostly pistillate. Lead 4
3 Spikes bisexual. Lead 32
4 Stigmas 2; achenes lenticular. Lead 5
4 Stigmas 3; achenes trigonous. Lead 11
5 Perigynia whitish-pulverulent or eventually turning golden orange at maturity; bract of the lowest pistillate spike obviously sheathing the culm; achenes dark brown at maturity. Lead 6
5 Perigynia green, becoming brown at maturity; bract of the lowest pistillate spike not sheathing the culm, or only barely so; achenes tan to brown at maturity. Lead 7
6 Terminal spikes staminate (rarely slightly pistillate); scales whitish to tawny; perigynia whitish-pulverulent, golden orange at maturity. C. aurea
6 Terminal spikes gynaecandrous or mostly so; scales brown to purplish; perigynia whitish-pulverulent at maturity. C. garberi
7 Beaks of the perigynia shallowly bidentate; perigynia 2-ribbed (with a single strong nerve along each edge), conspicuously nerved between the ribs. C. nebraskensis
7 Beaks of the perigynia entire; perigynia 2-ribbed and faintly nerved or nerveless between the ribs. Lead 8
8 Perigynia usually obovate, broadest near the apex but not inflated; leaves glaucous, the lower ones with well-developed blades. C. aquatilis
8 Perigynia usually ovate or elliptic, broadest at or below the middle, or if obovate, then inflated at the apex when mature; leaves green, the lower ones bladeless, short and pointed, brown or reddish, sheathing the culm base. Lead 9
9 Perigynia flattened, ovate to elliptic, not inflated, green at the apex, golden to tawny toward the base, sometimes eventually brown. Lead 10
9 Perigynia inflated at the apex, round-obovate, pale brown, often with darker brown spots. C. haydenii
10 Basal sheaths disintegrating into ladderlike fibers; ligule at juncture of leaf blade and sheath V-shaped, longer than wide. C. stricta
10 Basal sheaths not ladder-fibrillose; ligule truncate or low-rounded, wider than long. C. emoryi
11 Beak of the perigynium entire or obliquely cut (bidentulate). Lead 12
11 Beak of perigynia bidentate. Lead 20
12 Terminal spike staminate, pistillate or gynaecandrous, considerably larger than the lateral spikes. Lead 13
12 Terminal spike usually staminate throughout and smaller than or equal to the lateral spikes. Lead 14
13 Pistillate scales acuminate, awn-tipped; perigynia 2.5-3.5 mm long. C. buxbaumii
13 Pistillate scales obtuse, acute or mucronate; perigynia 1.5-2.3 mm long. C. hallii
14 Pistillate spikes drooping on lax, filiform peduncles. Lead 15
14 Pistillate spikes not drooping. Lead 16
15 Perigynia flattened, the beak less than 0.5 mm long; bract subtending the lowest pistillate spike sheathless or nearly so. C. limosa
15 Perigynia nearly terete, the beak 0.5 mm or more long; bract subtending the lowest pistillate spike with a well developed sheath. C. capillaris
16 Perigynia distinctly beaked, the beaks 0.5-1 mm long; pistillate spikes sessile or nearly so, the lower ones sometimes very short-peduncled. C. viridula
16 Perigynia obscurely beaked, the beaks nearly obsolete; pistillate spikes mostly peduncled (sessile in C. crawei). Lead 17
17 Perigynia 2-ribbed (with 2 prominent nerves), otherwise nerveless or with fewer than 10 faint nerves. Lead 18
17 Perigynia 2-ribbed, with more than 10 additional strong nerves. Lead 19
18 Pistillate spikes closely flowered; perigynia in 6 rows. C. meadii
18 Pistillate spikes loosely flowered; perigynia in 3 rows. C. tetanica
19 Plants tufted; staminate spikes short-peduncled or sessile; upper pistillate spikes aggregate. C. granularis
19 Plants with prolonged rhizomes; staminate spikes long-peduncled; pistillate spikes separate. C. crawei
20 Spikes on flexuous peduncles, drooping or widely spreading. Lead 21
20 Spikes on short erect peduncles or sessile. Lead 23
21 Perigynia sessile or nearly so, subterete, thin-textured, rather abruptly tapered to the beak, ascending to widely spreading in the spikes; teeth of the perigynium beak straight or nearly so, to 0.8 mm long. C. hystericina
21 Perigynia stipitate, trigonous-flattened, coriaceous and firm, gradually tapered to the beak, mostly reflexed in the spikes at maturity; teeth of the perigynium beak straight or recurved, 0.6-2 mm long. Lead 22
22 Teeth of the perigynium beak 1.2-2 mm long, ultimately recurved. C. comosa
22 Teeth of the perigynium beak 0.6-1 mm long, straight or nearly so. C. pseudo-cyperus
23 Perigynia pubescent; style jointed with the achene. Lead 24
23 Perigynia glabrous; style continuous with the achene. Lead 25
24 Leaves flat, 2-5 mm wide. C. lanuginosa
24 Leaves involute, 2 mm or less wide. C. lasiocarpa
25 Pistillate spikes 15-30 mm thick; perigynia 10-20 mm long. C. lupulina
25 Pistillate spikes 8-15 mm thick; perigynia 3.5-11 mm long. Lead 26
26 Perigynia strongly 7- to 9-nerved, inflated; style strongly S-curved toward the base. Lead 27
26 Perigynia with 10 or more nerves, slightly to strongly inflated; style straight. Lead 29
27 Bracts of the pistillate spikes several to many times longer than the inflorescence; perigynia widely spreading, the lower ones reflexed. C. retrorsa
27 Bracts of the pistillate spikes shorter than to somewhat exceeding the inflorescence; perigynia ascending to spreading. Lead 28
28 Perigynia in 8-10 rows, spreading; base of culm spongy-thickened; leaf sheaths strongly nodulose, with conspicuous cross markings between the nerves. C. rostrata
28 Perigynia in 6-8 rows, ascending; base of culm not spongy-thickened; leaf sheaths not conspicuously nodulose. C. vesicaria
29 Teeth of the perigynia less than 1 mm long, erect or slightly curved. Lead 30
29 Teeth of the perigynia 1-3 mm long, straight or recurved. Lead 31
30 Mature perigynia conspicuously many-nerved, the nerves elevated; plant base purple-tinged, the lowest leaf sheaths bladeless. C. lacustris
30 Mature perigynia inconspicuously nerved, the nerves impressed or level with the surface; plant base whitish or brownish, the lowest leaf sheaths with blades. C. hyalinolepis
31 Sheaths pubescent; teeth recurved. C. atherodes
31 Sheaths glabrous; teeth straight. C. laeviconica
32 Spikes androgynous. Lead 33
32 Spikes gynaecandrous or only the terminal spike gynaecandrous (or rarely staminate in C. interior), the lateral ones then pistillate. Lead 44
33 Culms arising singly or few together from axils of leaves on older reclining culms; plants of wet sphagnum bogs. C. chordorrhiza
33 Culms arising from tufts or rhizomes; plants of various habitats, mostly not found in sphagnum bogs. Lead 34
34 Beaks of the perigynia entire or obliquely cut. Lead 35
34 Beaks of the perigynia distinctly bidentate at the apex. Lead 40
35 Perigynia rounded on the margins; spikes few-flowered, with 1-6 perigynia and 1 or 2 staminate flowers. C. disperma
35 Perigynia sharp-edged, at least between the beak and the body. Lead 36
36 Plants forming colonies by long-creeping rhizomes, the culms arising singly or few together. Lead 37
36 Plants tufted, forming dense clumps; rhizomes none or very short. Lead 39
37 Leaf sheaths hyaline ventrally, truncate at the summit; ligule inconspicuous. Lead 38
37 Leaf sheaths green-striate ventrally, prolonged into a conspicuous, hyaline, tubular ligule. C. sartwellii
38 Perigynia blackish-brown at maturity, (2.5)3-4 mm long, the beak 1/2 or more the length of the body; rhizomes and lower leaf sheaths dark brown to black. C. praegracilis
38 Perigynia chestnut brown at maturity, 1.7-2.8 mm long, the beak 1/5-1/3 the length of the body; rhizomes and lower leaf sheaths light brown. C. simulata
39 Ventral surface of the leaf sheath white-hyaline or only slightly copper-tinged at the mouth; spikes closely aggregated; perigynia shiny. C. diandra
39 Ventral surface of the leaf sheath copper-colored, at least at the mouth; lower spikes more or less separate; perigynia dull. C. prairea
40 Spikes single at each node, usually less than 10 in the head; sheaths tight, not cross-rugulose ventrally. Lead 41
40 Spikes 2 or more on a branch at the lower nodes; sheaths usually cross-rugulose ventrally (not cross-rugulose in C. alopecoidea). Lead 42
41 Perigynia hidden in the head by scales; scales awn-tipped; leaves 1-2.5 mm wide. C. hookerana
41 Perigynia conspicuous in the head; scales acuminate to cuspidate; leaves 3-8 mm wide. C. gravida
42 Body of the perigynium gradually tapering into the beak, or if abruptly contracted, then the culms winged and flattened under pressure; culms 1.5-3.5 mm wide when pressed. Lead 43
42 Body of the perigynium abruptly contracted into the beak; culms not winged or flattened under pressure, 0.5-1.5 mm wide. C. vulpinoidea
43 Perigynia ovate, rounded at the base, contracted into the beak; sheaths not cross-rugulose ventrally. C. alopecoidea
43 Perigynia truncate-rounded at the base, tapering into the beak; sheaths cross-rugulose ventrally. C. stipata
44 Perigynia filled to the margins by the achene; the margins at most sharp-edged, not thin-winged. Lead 45
44 Perigynia filled only in the central portion by the achene, the margins thin-winged at least on the upper 1/2. Lead 48
45 Lower spikes (when 3 or more) overlapping or nearly so in the head; perigynia widely spreading or the lower ones reflexed at maturity, spongy-thickened at the base, the achene occupying mainly the upper 2/3 of the perigynium body. Lead 46
45 Lower spikes usually widely separated in the head; perigynia ascending to spreading-ascending at maturity, not spongy-thickened at the base, the achene essentially filling the body of the perigynium. Lead 47
46 Teeth of the perigynium beak obscure, not exceeding 0.25 mm long; scales obtuse; common species. C. interior
46 Teeth of the perigynium beak sharp, 0.3-0.5 mm long; scales acute to short-cuspidate; rare species. C. sterilis
47 Perigynia 5-10 per spike, ultimately loosely spreading, with a distinct beak ca. 0.4 mm long or more; leaves 1-2.5 mm wide, green. C. brunnescens
47 Perigynia 10-30 per spike, ascending, with a minute beak 0.2 mm or less long; leaves 2-4 mm wide, grayish-green to glaucous. C. canescens
48 Lower bracts of the inflorescence many times longer than the heads. Lead 49
48 Lower bracts of the inflorescence little, if at all, longer than the heads, often not evident. Lead 50
49 Perigynia ca. 6X longer than wide. C. sychnocephala
49 Perigynia ca. 3X longer than wide. C. athrostachya
50 Perigynium beaks slender, subterete, slightly serrulate toward the tip, obliquely cut dorsally; plant of moderate elevations in the Black Hills. C. microptera
50 Perigynium beaks flattened, winged, serrulate to the tip, bidentate; plants more widespread. Lead 51
51 Sheaths of principal leaves green-striate ventrally except for a V-shaped hyaline area at the mouth; leaf blades 3-7 mm wide. Lead 52
51 Sheaths of principal leaves with a nerveless, white-hyaline band on the ventral side; leaf blades 0.5-4.5 mm wide. Lead 53
52 Spikes globose or subglobose, the tips of the perigynia widely spreading to reflexed at maturity. C. cristatella
52 Spikes oblong-ovoid, the tips of the perigynia appressed to ascending. C. tribuloides
53 Perigynia subulate to narrowly ovate-lanceolate, 2.5-4X longer than wide, the marginal wings narrow their entire length. C. scoparia
53 Perigynia ovate-lanceolate, ovate or orbicular, not more than 2X longer than wide, the marginal wings broad their entire length. Lead 54
54 Perigynia ovate-lanceolate or narrowly ovate, (2.2)2.1 mm wide or less. Lead 55
54 Perigynia suborbicular or orbicular, (2)2.2 mm wide or wider. Lead 56
55 Spikes usually loosely arranged in drooping, moniliform heads, at least the lower spikes usually not overlapping in the head; perigynia stramineous at maturity, the ventral surface nerved. C. tenera
55 Spikes aggregated into compact heads, strongly overlapping; perigynia brown at maturity, the ventral surface nerveless. C. bebbii
56 Perigynia (4)5-7 mm long, membranous, thin except where distended by the achene, conspicuously nerved ventrally and dorsally. C. bicknellii
56 Perigynia 3-4.5 mm long, firm-textured, thickened, plano-convex; nerveless or obscurely few-nerved ventrally, faintly nerved dorsally. C. brevior


62. Cyperaceae, the Sedge Family
2. Carex L. -- Sedge
1. Carex alopecoidea Tuckerm.
2. Carex aquatilis Wahl. -- Water sedge
3. Carex atherodes Spreng. -- Slough sedge
4. Carex athrostachya Olney
5. Carex aurea Nutt. -- Golden sedge
6. Carex bebbii Olney ex Fern.
7. Carex bicknellii Britt. -- Bicknell's sedge
8. Carex brevior (Dewey) Mack. ex Lunell -- Fescue sedge
9. Carex brunnescens (Pers.) Poir.
10. Carex buxbaumii Wahl.
11. Carex canescens L.
12. Carex capillaris L.
13. Carex chordorrhiza Ehrh. ex L.f.
14. Carex comosa F. Boott
15. Carex crawei Dewey
16. Carex cristatella Britt.
17. Carex diandra Schrank
18. Carex disperma Dewey
19. Carex emoryi Dewey
20. Carex garberi Fern.
21. Carex granularis Muhl. ex Willd. -- Meadow sedge
22. Carex gravida Bailey -- Heavy sedge
23. Carex gynocrates Wormskj. ex Drej.
24. Carex hallii Olney
25. Carex haydenii Dewey
26. Carex hookerana Dewey
27. Carex hyalinolepis Steud. -- Thinscale sedge
28. Carex hystericina Muhl. ex Willd. -- Bottlebrush sedge
29. Carex interior Bailey
30. Carex lacustris Willd.
31. Carex laeviconica Dewey -- Smoothcone sedge
32. Carex lanuginosa Michx. -- Woolly sedge
33. Carex lasiocarpa Ehrh.
34. Carex leptalea Wahl.
35. Carex limosa L.
36. Carex lupulina Willd. -- Hop sedge
37. Carex meadii Dewey -- Mead's sedge
38. Carex microptera Mack.
39. Carex nebraskensis Dewey -- Nebraska sedge
40. Carex praegracilis W. Boott -- Clustered field sedge
41. Carex prairea Dewey
42. Carex pseudo-cyperus L.
43. Carex retrorsa Schwein.
44. Carex rostrata Stokes ex With. -- Beaked sedge
45. Carex sartwellii Dewey
46. Carex scoparia Schkuhr ex Willd. -- Broom sedge
47. Carex simulata Mack.
48. Carex sterilis Willd.
49. Carex stipata Muhl. ex Willd. -- Saw-beak sedge
50. Carex stricta Lam.
51. Carex sychnocephala Carey
52. Carex tenera Dewey
53. Carex tetanica Schkuhr
54. Carex tribuloides Wahl.
55. Carex vesicaria L.
56. Carex viridula Michx.
57. Carex vulpinoidea Michx. -- Fox sedge

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