Plants usually densely cespitose, rarely colonial, short-rhizomatous. Culms brown at base. Leaves: basal sheaths somewhat fibrous; sheath fronts membranous or herbaceous and not differentiated; blades V-shaped in cross section when young, smooth, sometimes minutely papillose. Inflorescences racemose, with 2–20+ spikes, 1–1.5 times as long as wide in fruit; proximal bracts scalelike or bristlelike, rarely leaflike, not more than 5 cm, not more than 2 times as long as inflorescences, sheathless; lateral spikes gynecandrous or pistillate, sessile, not prophyllate; terminal spikes gynecandrous. Proximal pistillate scales with apex obtuse to acuminate or awned. Perigynia erect to spreading, veined or veinless on both faces, sometimes stipitate, linear to orbiculate, flat to plano-convex, base tapering to rounded, margins winged or rarely narrowly ridged, entire, apex tapering to rounded to beak, smooth or, rarely, papillose; beak with abaxial suture, margins entire, apex bidentatate. Stigmas 2. Achenes biconvex, smaller than bodies of perigynia, with short apiculus formed by persistent base of style; style deciduous, base not enlarged.

Distribution

North America, Mexico, West Indies, Bermuda, Central America, South America, Eurasia.

Discussion

Species ca. 85 (72 in the flora).

The complex and difficult sect. Ovales is the largest section of Carex in North America. Only a few species in the section are found outside North America.

Fully mature perigynia are a prerequisite for keying. Perigynium measurements are best taken from perigynia about 1/3 of the spike length. Perigynia become distinctly marrower near the top of the spikes and the proximalmost few perigynia in the spikes are often shorter and wider than usual and sometimes deformed. Before choosing which lead in the key to follow, several perigynia should be sampled to assess variation in veination, shape, and size. Dimensions of the larger perigynia and achenes should be used in keying. Inflorescence characters are best taken from inflorescences produced by the first flush of growth in the spring. Many species continue to flower sporadically through the spring and summer, but especially in species with elongated, open or nodding inflorescences, the later inflorescences tend to be congested, ± erect, with more numerous spikes with shorter staminate bases, and with the proximalmost bracts longer and more leaflike. Those late-season forms are not accounted for in the key or descriptions, and plants collected late in the season lacking intact spring inflorescences may be impossible to key.

Keys

Key to Carex Sect. Ovales East of the Rocky Mountains

1 Pistillate scales uniformly as long as or longer than mature perigynia, usually concealing beaks (though not necessarily bodies), apex obtuse to acuminate, not awned. > 2
1 Pistillate scales (awns, if any, excluded) shorter than perigynia at least in middle portions of spikes, apical portion narrower than beaks and not completely covering them, apex awned in some species. > 11
2 Perigynia 6–8 mm at longest; inflorescences stiffly erect; high plains near Rocky Mountain foothills and Cypress Hills in Alberta and Saskachewan. Carex petasata
2 Perigynia 2.9–6(–6.5) mm at longest; inflorescences stiffly erect or flexible and nodding; widespread. > 3
3 Pistillate scales as wide as and essentially covering perignyia bodies. > 4
3 Pistillate scales usually distinctly narrower than perignyia bodies. > 5
4 Scales reddish brown, hyaline margins 0–0.2 mm wide; perigynia strongly 7– 11-veined abaxially. Carex adusta
4 Scales whitish or yellowish, hyaline margins 0.3–0.7 mm wide; perigynia veinless or faintly veined abaxially. Carex xerantica
5 Perignyium beak cylindric, unwinged, ± entire for 0.4+ mm from apex. > 6
5 Perignyium beak flat, ciliate-serrulate to apex. > 8
6 Inflorescences usually ± nodding, spikes well separated; perigynia usually (3.7–)4.5–6.5 mm. Carex praticola
6 Inflorescences stiffly erect; spikes aggregated or ± separated; perigynia usually less than 4.5 mm. > 7
7 Inflorescences dense, 1–2 cm, the proximal internode 1.5–4.8 mm; perigynia dark gold to coppery brown with metallic sheen; pistillate scales usually obtuse; arctic, subarctic, and alpine. Carex macloviana
7 Inflorescences usually ± open, 1.5–4 cm, the proximal internode (2.5–)4–10 mm; perigynia gold or light brown, without metallic sheen; pistillate scales acute to acuminate; ruderal mostly near the east coast. Carex ovalis
8 Perigynia lanceolate, 0.9–1.4 mm wide; Maine. Carex oronensis
8 Perigynia ovate, obovate or elliptic, 1.5–3.2 mm wide; widespread. > 9
9 Principal leaves stiff, ± glaucous, often bearing auricles at base, summit of sheaths truncate, prolonged 1–4 mm beyond collar; flat margins of perigynia 0.5–0.8 mm wide; achenes 1–1.2 mm wide; maritime sand flats, dunes, and headlands. Carex silicea
9 Principal leaves pliable, green, almost always without auricles, summit of sheaths U-shaped, only slightly prolonged beyond collar; flat margins of perigynia 0.2–0.6 mm wide; achenes 1–1.7 mm wide; inland, sandy or rocky habitats. > 10
10 Perigynia ascending to spreading, strongly and evenly veined on adaxial face, finely granular-papillose; spikes (3–)7–15, distal usually densely aggregated. Carex argyrantha
10 Perigynia erect-ascending, often veinless on adaxial face or with few veins of unequal strength, smooth; spikes 3–7(–11), distal often ± separated. Carex foenea
11 Proximal 2–3 inflorescence bracts leaflike, without bristle tips, much longer than inflorescences, ± surrounding culms; pistillate scales acuminate to awned; western. Carex athrostachya
11 Proximal 2–3 inflorescence bracts scalelike, often with bristle tips, shorter than or equaling inflorescences, rarely ± leaflike; pistillate scales obtuse, acute, or acuminate; widespread. > 12
12 Perignyium beak cylindric, ± entire for 0.2–0.9 mm from apex; South Dakota, Canadian prairies, and Arctic. > 13
12 Perignyium beak flat, ciliate-serrulate nearly to apex; widespread. > 16
13 Perigynia 6–8 mm at longest; high plains near Rocky Mountain foothills and Cypress Hills in Alberta and Saskachewan. Carex petasata
13 Perigynia 2.8–5.2 mm at longest; more widespread. > 14
14 Perigynia green or straw colored to brown when mature, mostly lighter in color than pistillate scale bodies; distance from top of achene to beak tip at least 1/2 length of perigynium. Carex microptera
14 Perigynia dark gold to coppery brown or brownish black when overmature, not much different in color from pistillate scale bodies; distance from top of achene to perigynium tip 1/2 or less perigynium length. > 15
15 Pistillate scale margins and perigynium tips conspicuously white-hyaline; perigynium wings darker than body; treeless areas in arctic, subarctic, and alpine regions. Carex macloviana
15 Pistillate scale margins and perigynium tips not or barely white-hyaline; perigynium wings same color as body (sometimes margins of wings dark); moist openings among trees and shrub. Carex pachystachya
16 Pistillate scales in middle or proximal portions of spikes with apex acuminate with subulate tip or awned. > 17
16 Pistillate scales with apex obtuse, acute, or acuminate, sometimes inconspicuous in spikes. > 27
17 Perigynia 3.5–6.3 mm wide; Louisiana, Oklahoma, Texas. Carex tetrastachya
17 Perigynia 0.9–4 mm wide, widespread. > 18
18 Perigynia 2.6–4 times longer than wide, bodies lanceolate, 0.9–2 mm wide. > 19
18 Perigynia less than 2.5 times longer than wide, bodies lance-ovate, ovate, broadly elliptic, orbiculate, or obovate, 1.8–3.9 mm wide. > 20
19 Perigynia 0.9–1.3 mm wide; achenes 0.6–0.8 mm wide; inflorescences dense; proximal inflorescence internodes 2–3(–5) mm. Carex crawfordii
19 Perigynia 1.2–2 mm wide; achenes 0.7–1.1 mm wide; inflorescences dense to open; proximal internode 2–17 mm. Carex scoparia
20 Perigynia (5.8–)6–7.1 mm at longest; beak 2–2.8 mm; pistillate scales with apex white-hyaline, acuminate-awned, fragile, membranaceous, and often curled, midvein not extending to tip. Carex missouriensis
20 Perigynia (2.3–)2.5–5.9(–6.3) mm at longest; beak 0.85–2.2(–2.5) mm; pistillate scales with apex firm, greenish to reddish brown, straight, midvein extending to tip. > 21
21 Perigynium body obovate, often with conspicuous “shoulders;” leaves 2.5–6 mm at widest. Carex alata
21 Perigynium body elliptic, suborbiculate, or weakly obovate; leaves 1–3(–4.2) mm at widest. > 22
22 Perignyium body cuneately tapered to base, base subacute, body ± diamond shaped; inflorescences ± dense, stiffly erect, with 3–5 spikes. Carex suberecta
22 Perignyium body convexly tapered to base, base rounded, body ovate, elliptic, orbiculate or weakly obovate, inflorescences dense and erect or open and nodding, with 3–11 spikes. > 23
23 Larger perigynia (2.4–)2.6–3.6 mm wide; achenes 1.8–2.2 × 1.3– 1.5 mm. Carex shinnersii
23 Larger perigynia 1.8–2.6(–2.8) mm wide; achenes 1.1–1.8 × 0.6–1.3 mm. > 24
24 Scales with white-hyaline or pale yellowish margins; perigynia greenish to straw colored or pale brown, (2.3–)2.5–4(–4.2) mm, often indistinctly 0–4(–6)-veined adaxially. Carex festucacea
24 Scales with reddish brown margins; perigynia reddish brown, (3.8–)4–5.5 mm, conspicuously 5+-veined adaxially. > 25
25 Achenes 1.1–1.4 × 0.6–0.8 mm; inflorescences compact, often headlike, erect or stiffly bent; proximal internode 1.5–4.5 mm. Carex scoparia
25 Achenes 1.5–1.8 × 0.8–1.1 mm; inflorescences usually elongated, arched or nodding; proximal internode (2–)5–18 mm. > 26
26 Beak ascending, less than 1/2 length of the lance-ovate to weakly obovate perignyium body; lateral spikes with acute staminate bases mostly less than 2 mm; maritime, salt influenced habitats. Carex hormathodes
26 Beak widely spreading, more than 1/2 length of the suborbiculate perignyium body; lateral spikes with tapered staminate bases 2–6 mm; freshwater wetlands. Carex straminea
27 Perigynia 2 mm wide or less. > 28
27 Perigynia more than 2 mm wide. > 43
28 Perigynia thin, often not winged to base; leaf sheaths somewhat expanded towards apex, bearing narrow wings continuous with midvein and edges of leaf blade; blades 3–7.5 mm wide; vegetative shoots tall, conspicuous, with numerous leaves spaced along distal 1/2 of culm. > 29
28 Perigynia thicker, winged to base; leaf sheaths with ± rounded edges, not distinctly expanded towards apex; blades 1–4.5 mm wide (except in C. normalis); vegetative shoots usually inconspicuous, with relatively few leaves clustered at apex. > 31
29 Proximal perigynia of each spike spreading or recurved (at 80° angle or greater); spikes globose; pistillate scales hidden, 1.6–2.3 mm. Carex cristatella
29 Proximal perigynia of each spike appressed-ascending to somewhat spreading (at 30–75° angle); spikes subglobose to ovate-oblong; pistillate scales evident, 2–3 mm. > 30
30 Inflorescences straight, spikes overlapping; perigynia usually 40+, appressed-ascending (at 30–40° angle); leaf sheaths firm at summit. Carex tribuloides
30 Inflorescences usually flexible or nodding, proximal spikes usually separated; perigynia usually 15–40, spreading (at 40–75° angle to spike axis); leaf sheaths firm or friable at summit. Carex projecta
31 Perigynia (2.5–)2.6–4 times as long as wide, body lanceolate, distance from beak tip to top of achene 2.2–5 mm (sometimes to 1.8 mm in C. crawfordii with perigynia less than 1.3 mm wide). > 32
31 Perigynia less than 2.5 times as long as wide, body obovate, orbiculate, or ovate, distance from beak tip to top of achene 0.8–2.2 mm. > 34
32 Perigynia 0.9–1.3 mm wide; achenes 0.6–0.8 mm wide; inflorescences dense, erect; proximal internode 2–3(–5) mm. Carex crawfordii
32 Perigynia 1.2–2 mm wide; achenes 0.7–1.1 mm wide; inflorescences dense to open, arching or nodding; proximal internode 2–17 mm. > 33
33 Spikes ellipsoid; inflorescences compact to open and arching; pistillate scales acuminate; perigynia usually ascending. Carex scoparia
33 Spikes ovoid to globose; inflorescences open, usually nodding; pistillate scales acute; perigynia spreading. Carex tenera
34 Perigynium body obovate, widest distally. > 35
34 Perigynium body ovate, elliptic, or orbiculate, widest at or proximal to mid body. > 36
35 Perignyium beak appressed-ascending, triangular; pistillate scales obtuse; styles straight. Carex longii
35 Perignyium beak spreading, slender; pistillate scales acute; styles laterally sinuous at base. Carex albolutescens
36 Inflorescences on tallest culms compact, 1.5–3 times as long as wide, erect, spikes overlapping; the proximal internode 1–6(–7.5) mm, 1/2–1/5(–1/4) length of inflorescence. > 37
36 Inflorescences on tallest culms elongate, ± open proximally, (2.5–)3–5.1 times as long as wide, often arching or nodding; spikes ± separate; proximal internode (5–)7–19 mm, mostly 1/5–1/3(–1/2) length of inflorescence. > 40
37 Achenes 0.6–0.9 mm wide; perigynia veinless or 1–3-veined adaxially, veins faint or basal; inflorescences less than 30 mm. Carex bebbii
37 Achenes 0.9–1.3 mm wide; perigynia often 3-veined adaxially; inflorescences 12–60 mm. > 38
38 Perigynia broadly elliptic or nearly orbiculate, wing margin 0.4– 0.8 mm wide, 0–6 veined adaxially. Carex molesta
38 Perigynia ovate to broadly ovate, wing margin 0.25–0.45 mm wide, 4–7-veined adaxially. > 39
39 Sheaths smooth, whitish mottled, inner band not corrugated; perigynia greenish at maturity. Carex normalis
39 Sheaths finely papillose (at 30X), not whitish mottled, the inner band sometimes corrugated; perigynia brown at maturity. Carex tincta
40 Perignyium orbiculate, widest at mid body. Carex festucacea
40 Perignyium narrowly to broadly ovate, widest proximal to mid body. > 41
41 Sheaths, at least some, papillose near collar (at 30X), not prominently whitish mottled; perignyium beak appressed or ascending in spikes, exceeding pistillate scales by 0–0.8 mm; beak and shoulders of perigynia straw colored to reddish brown at maturity. Carex tenera
41 Sheaths smooth, often whitish mottled; perignyium beak spreading, exceeding pistillate scales by 0.7–1.6 mm; beak and shoulders of perigynia greenish to yellowish or greenish brown at maturity. > 42
42 Inflorescences erect to somewhat bent; proximal internode mostly 6–10(–11.5) mm; rachis stiff; leaves 2.2–6.5 mm wide; larger perigynia mostly 2.7–4.1 mm and 1.8–2.2 times as long as wide; plants forming small, ± erect clumps of fewer than 40 culms. Carex normalis
42 Inflorescences arching or nodding; proximal internode (6–)10–21 mm; rachis usually thin, wiry; leaves 1.5–3.5(–3.7) mm wide; larger perigynia mostly (3.4–)3.6–4.6 mm, (1.9–)2.1–2.8(–3.2) times as long as wide; plants often forming large, spreading, nodding clumps of many culms. Carex tenera
43 Spikes 12–28 mm with tapered base and acute apex; perigynium body lanceolate, 6–9 mm; vegetative culms conspicuous. Carex muskingumensis
43 Spikes either shorter than 12 mm or longer and with either rounded bases or apices or both; perigynium body ovate, elliptic, orbiculate, or obovate or, if lanceolate, shorter than 6 mm; vegetative culms conspicuous or not. > 44
44 Perignyium bodies obovate, widest distally; leaf sheaths green veined adaxially nearly to summit or with narrow Y-shaped hyaline area. > 45
44 Perignyium body lanceolate, ovate, elliptic, orbiculate, or reniform, widest at or proximal to middle; leaf sheaths various, some with prominent hyaline band near apex adaxially. > 51
45 Achenes 1.3–1.8 mm at widest. Go to couplet 57
45 Achenes 0.75–1.2(–1.3) mm at widest. > 46
46 Inflorescences erect, 1–4.5 cm; spikes slightly separated to congested, base rounded to acute, staminate portion of spike less than 2 mm. > 47
46 Inflorescences arching or nodding, 2.3–8.4 cm; spikes widely separated; spikes clavate. > 50
47 Perignyium beak spreading, narrow triangular, distance from beak tip to top of achene 1–2 mm; styles with strong lateral sinuosity at base. Carex albolutescens
47 Perignyium beak appressed-ascending, broad triangular, distance from beak tip to top of achene (1.4–)2+ mm; styles straight or occasionally sinuous near middle. > 48
48 Perigynia veinless on adaxial face; leaves 3–6(–8) mm at widest; sheaths truncate at summit and extending 0.3 mm beyond collar. Carex cumulata
48 Perigynia veined on adaxial face; leaves 2–4(–4.5) mm at widest; sheaths concave at summit and not prolonged beyond collar. > 49
49 Pistillate scales white-hyaline to pale silvery-brown, obtuse; achenes 0.7–1 mm wide, apiculum less than 0.4 mm; widespread. Carex longii
49 Pistillate scales reddish brown, acute; achenes 0.9–1.2 mm wide, apiculum 0.4–0.8 mm; Ozark Mountains and vicinity. Carex ozarkana
50 Sheaths finely papillose (at 30X), summits truncate, prolonged 1–4 mm beyond collar; pistillate scales white-hyaline; coastal. Carex silicea
50 Sheaths smooth, summits concave, only reaching base of leaf blade; pistillate scales yellowish to reddish brown; Ozark mountains and vicinity. Carex ozarkana
51 Plants colonial; rhizomes short-creeping; vegetative culms numerous, conspicuous, strongly 3-ranked, with 15–35 leaves when fully developed; achenes 1.6–2 times as long as wide (and 0.9–1.2 mm wide); larger spikes with 5–25(–30) perigynia. Carex hyalina
51 Plants clumping; rhizomes may appear elongate in old clumps; vegetative culms few, inconspicuous, usually with fewer than 15(–17) leaves, not strikingly 3-ranked; achenes 1–1.6(–1.7) times as long as wide, 0.9–2.2 mm wide; larger spikes with 15–80 perigynia. > 52
52 Perigynia finely granular-papillose (30X), body reniform to orbiculate, 0.6–0.9 times as long as wide, 3.5–4.5(–4.9) mm wide; proximal pistillate scale obtuse-rounded. Carex reniformis
52 Perigynia smooth, body broadly ovate, elliptic, ± orbiculate, or rarely slightly obovate, (0.7–)0.9–1.7 times as long as wide, 1.5–6.1 mm wide; proximal pistillate scale obtuse to acuminate-awned. > 53
53 Perigynia 5.5–8(–8.7) × (3.1–)3.3–6.3 mm at largest (except sometimes in C. bicknellii and C. shinnersii), often prominently bulged on both faces; beak (1.4–)1.6–2.5(–3.4) mm. > 54
53 Perigynia 2.5–5.5 × 2–3.6 mm at largest (to 6.1 × 4.4 mm in the Florida endemic C. vexans), prominently bulged by achene only on abaxial face or flat; beak usually 0.7–1.6(–1.8) mm. > 58
54 Perigynia 3.5–6.3 mm at widest, veinless over achenes adaxially or nearly so; at least proximal staminate scales, especially of terminal spike and sometimes proximal pistillate scales, with midvein excurrent as scabrous awn 0.1–0.9(–2.4) mm; larger culms with 2–4(–5) spikes. Carex tetrastachya
54 Perigynia (2.5–)2.7–4.8 mm at widest, (0–)1–8-veined over achene adaxially; staminate and pistillate scales obtuse to acuminate-awned, midvein not excurrent as scabrous awn; larger culms with (3–)4–7(–11) spikes. > 55
55 Leaf sheaths finely papillose, at least near apex; perigynia membranaceous, with brown achene clearly visible through hyaline adaxial face, usually with reddish brown tinged wings, strongly, evenly 4–8-veined adaxially over achene; pistillate scales usually reddish brown; anthers (2.4–)2.8–4.2 mm; plants in small clumps (usually fewer than 25 culms) in dry to mesic habitats. Carex bicknellii
55 Leaf sheaths smooth; perigynia herbaceous, opaque, with achene not clearly visible through adaxial face, with greenish or pale brown wings, finely and irregularly (0–)1–7-veined over achene adaxially; pistillate scales pale yellowish brown to brown; anthers (1.8–)2.2–3.6 mm; plants often in dense, large clumps (to 200 culms) in wet habitats. > 56
56 Staminate and pistillate scales acuminate-awned, tip white to brownish hyaline, membranaceous, often ± curled, midvein fading before tip; beak of larger perigynia 2–2.6(–2.8) mm; body (1.3–) 1.4–2.1 times as long as beak. Carex missouriensis
56 Staminate and pistillate scales obtuse to acuminate, tip firm, herbaceous, flat or inrolled, midvein prominent to tip; beak (1.2–)1.5–2.1(–2.3) mm; body 1.9–3 times as long as beak. > 57
57 Perigynia (5.6–)6–7.1 × 3.3–4.6(–4.8) mm, exceeding subtending scale by 1.5–2.6 mm; staminate and proximal pistillate scales obtuse to acute; pistillate scales 2.4–3.2(–3.4) times as long as wide. Carex opaca
57 Perigynia (4.5–)4.8–6(–6.3) × 2.5–3.8 mm, exceeding subtending scale by (0.4–)0.6–1.4(–1.6) mm; staminate and proximal pistillate scales acuminate; pistillate scales (2.6–)2.9–3.7(–4.2) times as long as wide. Carex shinnersii
58 Leaf sheaths green-veined adaxially nearly to summit; inflorescences dense to ± open, erect, the proximal internode usually less than 8(–12) mm. > 59
58 Leaf sheaths with white-hyaline area adaxially; inflorescences open or dense. > 60
59 Perigynia with acute bases, 2–2.8 mm wide; beak appressed, 2/5+ length of body; broadest leaves 1.5–2.5 mm wide; n, w North America. Carex suberecta
59 Perigynia with rounded bases, 3–4.4 mm wide; beak spreading, 1/3 length of body; leaves 2–5 mm at widest; Florida. Carex vexans
60 Perigynium body narrowly to broadly ovate, greenish; pistillate scales with green midstripe, hyaline or pale margins, rarely brown tinged; leaves 2.5–6.5 mm wide, sheaths green mottled, with mouth truncate, and prolonged to 2 mm distal to base of leaf blades. Carex normalis
60 Perigynium body broadly ovate, broadly elliptic, or orbiculate, yellowish to tan brown; pistillate scales greenish or dark brown; leaves 1.5–4(–5) mm wide, sheaths usually evenly colored, with mouth concave (prolonged distal to base of leaf blades in C. merritt-fernaldii). > 61
61 Leaf sheaths finely papillose (at 30–40X), especially near leaf base. > 62
61 Leaf sheaths smooth. > 65
62 Perigynia strongly and evenly 4–8-veined over achene adaxially, (4.5–)5.1–5.5 mm; pistillate scales usually (1–)1.4–2.3 mm shorter than perigynia; anthers (2.4–)2.8–4.2 mm. Carex bicknellii
62 Perigynia veinless or faintly and irregularly 0–5(–6)-veined over achene adaxially, (2.3–)2.5–5.2(–5.5) mm; pistillate scales 0.2–1.3 mm shorter than perigynia; anthers (1–)1.3–2.6 mm. > 63
63 Pistillate scales reddish brown or dark brown; leaves of fertile shoots 2–4, sheaths with adaxial hyaline area sometimes puckered or cross-corrugated. Carex tincta
63 Pistillate scales greenish to yellowish; leaves of fertile shoots 3–6, sheaths not puckered. > 64
64 Perigynia 2.3–3.5 mm wide; distance from summit of achene to tip of beak 1.8–3.1 mm; achenes 1.1–1.5 mm wide. Carex merritt-fernaldii
64 Perigynia 1.5–2.3(–2.5) mm wide; distance from summit of achene to tip of beak 0.8–1.7(–2) mm; achenes 1–1.3 mm wide. Carex festucacea
65 Spikes on larger culms (3–)5–7(–11), tapered at base, terminal spike with conspicuous staminate base; inflorescences typically open, 2.5–4.5(–6.5) cm; proximal internode (3–)4–13(–23) mm; perigynium body (0.7–)0.9–1.3 times as long as wide (to 1.6 in C. shinnersii). > 66
65 Spikes on larger culm 2–4(–5), rounded at base, terminal spike usually lacking conspicuous staminate base; inflorescences compact, 1.2–3(–3.6) cm, the proximal internode 1.5–7(–13) mm; perigynium body (0.7–)0.9–1.6 times as long as wide. > 68
66 Achenes 1.2–1.8 × 1–1.3 mm at largest; perigynia 2.5–4.2 × 1.5–2.3 (–2.5) mm at largest, mostly 2–4(–6)-veined adaxially. Carex festucacea
66 Achenes (1.6–)1.7–2.2 × (1.2–)1.4–1.8 mm at largest; perigynia 3.2–5.5 ´ 2.5–3.6 mm at largest, veinless or faintly 1–5(–7)-veined adaxially. > 67
67 Perigynia 3.2–4.8(–5.2) mm at longest; beak 0.8–1.5 mm; pistillate scales 3.3–4(–4.3) mm, 2.3–2.9(–3.1) times as long as wide, acute; achenes 1–1.3(–1.4) times as long as wide. Carex brevior
67 Perigynia (4.6–)5–5.5 mm at longest; beak 1.4–2.2(–2.4); pistillate scales, (3.7–)4–5.2(–5.6) mm, (2.6–)2.9–3.7(–4.2) times as long as wide, acuminate to awned; achenes (1.2–)1.4–1.7 times as long. Go to couplet 56
68 Achenes of larger perigynia ellipsoid to narrowly oblong, 0.9–1.3 mm wide, 1.3–1.6 times as long as wide; perigynia (25–)30–80 per spike, squarrose-spreading at maturity, 2–2.8(–3) mm at widest. Carex molesta
68 Achenes of larger perigynia broadly oblong to ± orbicular, 1.35–1.8 mm wide, 1–1.3 times as long as wide; perigynia (10–)15–40(–45) per spike, appressed-ascending at maturity, (2.1–)2.5–3.4(–3.5) mm at widest. > 69
69 Perigynia veinless or faintly, irregularly 1–5-veined over achene adaxially, ± orbiculate, bodies (2–)2.3–3.2 mm, (0.7–)0.9–1.1(–1.3) times as long as wide; pistillate scales mostly acute, about as long as to 0.7(–0.9) mm shorter than subtended perigynium (flattened and measured separately); widespread. Carex brevior
69 Perigynia strongly 4–6-veined over achene adaxially, broadly ovate to broadly elliptic, less often ± orbiculate, bodies (2.7–)3–4 mm, (0.9–)1–1.6 times as long as wide; pistillate scales mostly obtuse, 0.7–1.7 mm shorter than subtended perigynium (flattened and measured separately); Ozark Mountains, Cumberland Plateau, c Appalachians. Carex molestiformis

Key to Carex Sect. Ovales West of the Rocky Mountains

1 Perigynium wings absent or entire throughout their length, 0–0.2 mm wide. > 2
1 Perigynium wings ciliate-serrulate at least on distal body, 0.1–1 mm wide. > 3
2 Inflorescences 1–1.2 cm; proximal internode 1.3–3 mm; perigynia wings absent, body 0.5–0.65 mm thick; marshes, bogs, wet meadows. Carex illota
2 Inflorescences 1.1–2.4 cm; proximal internode (1.5–)2.5–9.5 mm; perigynia wings 0.05–0.15(–0.2) mm wide, entire, body 0.4–0.5 mm thick; seasonally moist meadows, road sides. Carex integra
3 Proximal 2–3 bracts of most inflorescences elongate, ± leaflike, at least the proximal usually much longer than inflorescences; inflorescences dense, headlike. > 4
3 Proximal 2–3 bracts of most inflorescences scalelike or bristlelike, shorter than inflorescences, the proximal sometimes leaflike, longer than inflorescence; inflorescences dense or open. > 6
4 Achenes 0.5–0.7 mm thick, (0.9–)1–1.2(–1.4) mm wide; California. Carex harfordii
4 Achenes 0.3–0.4 mm thick, 0.7–1(–1.2) mm wide; California and elsewhere. > 5
5 Perigynia plano-convex or flat; beak usually cylindric, unwinged, ± entire at least 0.4 mm from tip; achenes sessile or shortly stipitate, near base of perigynium body; inflorescences ± erect. Carex athrostachya
5 Perigynia flat around achene; beak usually flat, winged, ciliate-serrulate to tip or, sometimes, cylindric, unwinged, ± entire less than 0.4 mm; achenes stipitate, near middle of perigynium body; inflorescences usually ascending. Carex unilateralis
6 Adaxial leaf sheaths thick and green-veined nearly to collar, with ± triangular white-hyaline area at collar extending at most 6 mm proximal to collar. > 7
6 Adaxial leaf sheaths white-hyaline or green-veined with central white-hyaline strip extending at least 10 mm proximal to collar. > 8
7 Spikes 6–12, base attenuate; leaf sheaths with rounded summit, prolonged 1.5–6 mm distal to collar; perigynia 0.4–0.5 mm thick, to 2.1 mm wide; native west of Rocky Mountains. Carex feta
7 Spikes 3–5(–6), base rounded; leaf sheaths with U-shaped summit. not prolonged distal to collar; perigynia 0.5–0.6 mm thick, 2–2.8(–3) mm wide; not native west of the Rocky Mountains (introduced in California). Carex molesta
8 Leaf sheaths prolonged adaxially at least 3 mm beyond collar, rounded to acute at summit; inflorescences silvery or pale green to gold. > 9
8 Leaf sheaths prolonged adaxially less than 2.8 mm beyond collar or, if more, prolonged, summit U-shaped or inflorescences darker, gold, brown, or green and brown. > 10
9 Perigynia (3.5–)4–5.2 mm at longest, (1.8)2–3 mm from beak tip to achene; beak flat, ciliate-serrulate to tip. Carex amplectens
9 Perigynia 2.9–4(4.8) mm at longest, 1.3–2(–2.8) mm from beak tip to achene; beak cylindric, ± entire for at least 0.1 mm from tip. Carex fracta
10 Perigynium body (excluding wings) flat except where distended by achene or very thinly concavo-convex. > 11
10 Perigynium body (excluding wings) plano-convex, biconvex, or thickly concavo-convex. > 26
11 Perignyium beak flat, ciliate-serrulate to tip; spikes distant and individually distinct. > 12
11 Perignyium beak cylindric, unwinged, ± entire for at least 0.2 mm from tip; spikes distant or densely aggregated, individually distinct or indistinct. > 18
12 Perigynia 0.9–1.25 mm wide, 0.15–0.3 mm thick; achenes 0.6–0.8 mm wide. Carex crawfordii
12 Perigynia 1.2–3.8 mm wide, 0.35–0.7 mm thick; achenes 0.85–2 mm wide (0.7–0.9 mm in C. scoparia). > 13
13 Perigynia lanceolate, at least 3 times as long as wide; achenes 0.7–0.9 mm wide. Carex scoparia
13 Perigynia lanceolate to broadly ovate, less than 2.8 times as long as wide; achenes 0.8–2 mm wide. > 14
14 Perigynia 5.2–7.5 mm, 0.5–0.7 mm thick, abaxial veins usually absent or obscure; pistillate scales 4.3–6.7 mm. > 15
14 Perigynia 3.4–5.8 mm, 0.3–0.5 mm thick, abaxial at least 3 veins conspicuous; pistillate scales 3.2–5.1 mm. > 16
15 Perigynia 2–3 mm wide, 2.4–2.7 times as long as wide; abaxial suture usually inconspicuous. Carex wootonii
15 Perigynia 2.7–3.8 mm wide, 1.8–2.3 times as long as wide; abaxial suture with conspicuous white-hyaline margin. Carex egglestonii
16 Perigynia 1.8–3.4 mm wide, 1.7–2.3 times as long as wide, thin, 10–20-veined abaxially, flat margin including wing 0.4– 1 mm wide, usually crinkled at least distally. Carex straminiformis
16 Perigynia 1.3–2.3 mm wide, 2.2–2.6 times as long as wide, thick, 0–9-veined abaxially, flat margin including wing 0.2–0.6 mm wide, not crinkled. > 17
17 Leaf blades becoming 3-angled toward tip, often channeled, 1–2(–3) mm wide; pistillate scales with white-hyaline margin 0.1–0.3 mm wide; perignyium beak brown to red-brown or gold, white-hyaline at tip; above 2500 m elevation. Carex phaeocephala
17 Leaf blades flat ± to tip, 1.5–4 mm wide; pistillate scales without white-hyaline margin, often with white-hyaline tip or base; perignyium beak red-brown at tip, without white-hyaline; below 1100 m elevation. Carex ovalis
18 Proximal inflorescence internode (2.5–)4–14 mm; spikes distant or loosely aggregated except sometimes dense in C. proposita. > 19
18 Proximal inflorescence internode 1–4(–4.8) mm; spikes densely aggregated (sometimes proximal 1 more distant). > 22
19 Pistillate scales 1/3–1/2 width of perigynia; perigynia margins often crinkled; anthers long-persistent. Carex proposita
19 Pistillate scales 2/3–1 width of perigynia; perigynia margins flat; anthers early deciduous or short-persistent. > 20
20 Perigynia 2.8–3.1 times as long as wide; beak cylindric, unwinged, ± entire for 0.4–1 mm from tip; inflorescences often moniliform or flexible. Carex praticola
20 Perigynia 2.2–2.6 times as long as wide; beak cylindric, unwinged, ± entire for 0.3–0.6 mm from tip; inflorescences ± stiff. > 21
21 Leaf blades becoming 3-angled toward tip, often channeled, 1–2(–3) mm wide; pistillate scales with white-hyaline margin 0.1–0.3 mm wide; perignyium beak brown to red-brown or gold with white-hyaline tip; above 2500 m elevation. Carex phaeocephala
21 Leaf blades flat ± to tip, 1.5–4 mm wide; pistillate scales without white-hyaline margin, often with white-hyaline tip or base; perignyium beak red-brown or gold at tip, without white-hyaline; below 1100 m elevation. Carex ovalis
22 Pistillate scales as long as perigynia, usually covering beaks; perignyium beak cylindric, unwinged, ± entire for 0.5–1.3 mm from tip; spikes 9– 12 mm. Carex arapahoensis
22 Pistillate scales usually shorter than perigynia, exposing at least beaks and distal body margins; perignyium beak cylindric, unwinged, ± entire for 0.2–0.8 mm from tip; spikes 4.4–11 mm. > 23
23 Perignyium beak usually less than 1 mm, cylindric, unwinged, ± entire for 0.5–0.8 mm from tip, body 3–8-veined adaxially. Carex abrupta
23 Perignyium beak usually at least 1 mm, cylindric, unwinged, ± entire for usually less than 0.6 mm from tip, body 0–8-veined adaxially. > 24
24 Perigynia 4–6.5 mm, usually at least (2.3–)2.6 mm from beak tip to achene; pistillate scales 3–4.8 mm; subalpine to alpine. Carex haydeniana
24 Perigynia 2.4–4.5(–5.2) mm, usually no more than 2.5 mm from beak tip to achene; pistillate scales 2.4–4.1 mm; lowlands to subalpine. > 25
25 Perigynia with glossy metallic sheen, pithlike tissue often present inside near perigynium base; leaf blades 4–18 cm; pistillate scale tips usually obtuse. Carex macloviana
25 Perigynia without metallic sheen, dull to slightly shiny, pithlike tissue absent; leaf blades 10–50 cm; pistillate scale tips acute. Carex microptera
26 Perigynia 0.15–0.35 mm thick, 0.9–1.25 mm wide. Carex crawfordii
26 Perigynia 0.35–0.9 m thick, 1–3.4 mm wide. > 27
27 Perigynia boat-shaped, less than 4.2 mm, with wings curved toward adaxial face, flat margins including wing 0.05–0.2 mm wide; beak tips inconspicuous in inflorescences. Carex leporinella
27 Perigynia usually not boat-shaped and less than 4.2 mm, with wings adaxially incurved or, if perigynia boat-shaped and wings adaxially incurved, then flat margin including wing at least 0.2 mm wide; beak tips conspicuous in inflorescences. > 28
28 Perigynia conspicuously veined adaxially, at least 3 veins longer than achene. > 29
28 Perigynia essentially veinless adaxially, faintly 0–10-veined, or conspicuously 0–5-veined, veins shorter than achene. > 44
29 Spikes densely aggregated or sometimes proximal 1 more distant; proximal inflorescence internode usually 1–4 mm. > 30
29 Spikes distant, loosely aggregated, or closely aggregated only distally; proximal inflorescence internode 4–12 mm. > 37
30 Perigynia usually at least 7-veined abaxially; perigynia 0.5–0.8 mm thick; achenes 1–1.7 mm wide. > 31
30 Perigynia fewer than 7-veined abaxially or, if more than 7, perigynia 0.4–0.55 mm thick and achenes 0.6–1.3 mm wide. > 32
31 Perigynia ovate to broadly ovate, usually more than (1.4–)1.8 mm wide, 2–2.8(–3.3) mm from beak tip to achene; inflorescences usually ± triangular, with 4–6(–10) spikes; spikes (8.5–)10–12 mm. Carex multicostata
31 Perigynia lanceolate to ovate, usually less than 1.8(–2) mm wide, 2.7–4.2 mm from beak tip to achene; inflorescences usually oblong, with 5–14 spikes; spikes 9–18 mm. Carex specifica
32 Perigynia 4–7.1 mm, 2.2–4 mm from beak tip to achene; pistillate scales shorter than perigynia, narrower than or ± as wide as perigynia. > 33
32 Perigynia 1.4–5.4 mm, 1.2–2.5 mm from beak tip to achene or, if to 2.6 mm from beak tip to achene, pistillate scales ± covering perigynia. > 34
33 Perigynia 5.3–7.1 mm; inflorescences 14–20 mm wide. Carex ebenea
33 Perigynia 4–5.1 mm; inflorescences 8–15 mm wide. Carex stenoptila
34 Adaxial veins of perigynia thin, extending to base of beak, beak tip reddish, coppery, or brown, (1.5–)2–2.3 mm from beak tip to achene. > 35
34 Adaxial veins of perigynia thick, not extending beyond top of achene, beak tip white, green, gold, or brown, 1.2–2(–2.5) mm from beak tip to achene. > 36
35 Proximal 2 inflorescence internodes collectively less than 1/3 as long as inflorescences. Carex abrupta
35 Proximal 2 inflorescence internodes collectively more than 1/3 as long as inflorescences. Carex mariposana
36 Perigynia 0.6–0.7 mm thick; achenes (1.3–)1.5–1.9 mm. Carex harfordii
36 Perigynia 0.4–0.5(–0.6) mm thick; achenes 1–1.6 mm. Carex subfusca
37 Larger perigynia 6–8.5 mm. > 38
37 Larger perigynia less than 6 mm. > 40
38 Staminate scales with white-hyaline margin (0-2–)0.3–0.7 mm wide; pistillate scales ± equaling, covering perigynia, white-hyaline or with white-hyaline margin 0.2–0.7 mm wide. Carex petasata
38 Staminate scales with white-hyaline margin 0–0.4 mm wide; pistillate scales 2/3–3/4 length of or equaling perigynia, with white-hyaline margin 0–0.4 mm wide. > 39
39 Spikes 2–3, 5.5–7 mm wide; pistillate scale tips acute; Sierra Nevada, California. Carex davyi
39 Spikes 3–7, 7–10 mm wide; pistillate scale tips obtuse; Mount Adams, Washington. Carex constanceana
40 Achenes 1–1.6 mm; perigynia 2.4–4(–4.3) mm. Carex subfusca
40 Achenes 1.5–2.4 mm; perigynia 3.4–6 mm. > 41
41 Pistillate scales white or tinged pale gold; inflorescences 40– 65 mm; proximal internode 7–20 mm; 2d internode 4–8.5 mm. Carex amplectens
41 Pistillate scales gold to brown, often reddish, with white-hyaline margin 0–0.6 mm wide; inflorescences 15–40 mm; proximal internode 3.5–11 mm; 2d internode 2–7 mm (inflorescences to 48 mm; proximal and 2d internode 3.5–7.5 and 2.5–5 mm, respectively, in C. mariposana). > 42
42 Perigynia appressed or appressed-ascending, (0.6–)1–2 mm from beak tip to achene; pistillate scales with white margin 0.2–0.6 mm wide; achenes 0.5–0.7 mm thick. Carex tahoensis
42 Perigynia ascending, 1.5–2.6 mm from beak tip to achene; pistillate scales with white-hyaline margin 0–0.3 mm wide; achenes 0.3–0.6 mm thick. > 43
43 Perigynia 1.5–2.3 mm wide, flat margin including wing 0.3–0.5 mm wide, beak sometimes white-hyaline at tip; pistillate scales lanceolate to ovate, usually ± covering perigynia. Carex phaeocephala
43 Perigynia 1.1–1.6(–2.2) mm wide, flat margin including wing 0.15–0.4 mm wide, beak tip not white-hyaline; pistillate scales ovate to broadly ovate, usually shorter than perigynia. Carex mariposana
44 Perignyium beak flat, ± ciliate-serrulate to tip or cylindric, unwinged, ± entire for less than 0.4 mm from tip. > 45
44 Perignyium beak cylindric, unwinged, ± entire for at least 0.4 mm from tip. > 57
45 Perigynia broadly ovate to orbiculate, 1.2–1.8 times as long as wide. > 46
45 Perigynia narrowly to broadly ovate or elliptic, 1.9–2.7 times as long as wide. > 47
46 Spikes on larger culms 5–7, base attenuate, terminal spike with conspicuous staminate base; inflorescences usually 25–50 mm; achenes 1.3–1.8 mm wide. Carex brevior
46 Spikes on larger culms mostly 3–4, base rounded, terminal spike without conspicuous staminate base; inflorescences 13–35 mm; achenes 0.9–1.3 mm wide. Carex molesta
47 Proximal inflorescence internode usually 1–4 mm; spikes densely aggregated. > 48
47 Proximal inflorescence internode at least 3 mm; spikes distant or loosely aggregated. > 51
48 Perigynia reddish brown, 0.35–0.45 mm thick, 1.9–2.1 times as long as wide; achenes 0.6–0.9 mm wide. Carex bebbii
48 Perigynia green, straw colored, gold, light to coppery brown, or whitish, 0.4–0.7 mm thick, 2.1–2.7 times as long as wide; achenes 0.7–1.5 mm wide. > 49
49 Achenes 1–1.6 × 0.7–1.25 mm; inflorescences appearing fine-textured. Carex subfusca
49 Achenes 1.3–2 × 0.9–1.5 mm; inflorescences appearing more coarse-textured. > 50
50 Proximal inflorescence internode 1.5–2.5 mm; 2d internode 1–2.5 mm; adaxial leaf sheaths usually brown- or gold tinged near summit; coastal California to 600 m elevation. Carex harfordii
50 Proximal inflorescence internode 3–7 mm; 2d internode 1–4 mm; adaxial leaf sheaths white-hyaline; inland West 1000-3400 m elevation. Carex preslii
51 Achenes 1–1.7(1.9) mm; pistillate scales usually 2.1–3.5 mm; perigynia less than 4.5 mm. > 52
51 Achenes 1.5–2.7 mm; pistillate scales 2.8–6.2 mm; perigynia 3.3–7.5 mm. > 53
52 Perigynia 2–2.3 times as long as wide, brown; culms often nodding; inflorescences (20–)25–50 mm, often flexible; 2d internode (3–)6–10 mm. Carex tenera
52 Perigynia 2.1–2.7 times as long as wide, green, straw colored, or light brown, often white over achene; culms not nodding; inflorescences 11– 30 mm, not flexible; 2d internode 1–6 mm. Carex subfusca
53 Perigynia 5.4–7.5 mm, flat margin including wing 0.5–0.8 mm wide; achenes 1.4–2 mm wide. Carex wootonii
53 Perigynia 3.3–5.2 mm or, if longer, flat margin including wing less than 0.5 mm wide; achenes (0.8–)1–1.3(–1.7) mm wide. > 54
54 Inflorescences flexible; spikes usually distant; proximal 2 internodes collectively 9–37 mm; perigynia 0.6–0.8 mm thick. Carex foenea
54 Inflorescences stiff; spikes aggregated to distant; proximal 2 internodes collectively 4–18 mm; perigynia 0.4–0.6 mm thick (to 0.8 mm thick in Carex preslii, which has proximal 2 inflorescence internodes collectively 4–11 mm). > 55
55 Perigynia essentially erect, faintly 8–10-veined abaxially. Carex xerantica
55 Perigynia appressed-ascending to ascending-spreading, conspicuously 0–8-veined abaxially. > 56
56 Spikes 7–10 mm; perigynia biconvex or plano-convex, flat margin including wing 0.2–0.4 mm wide. Carex preslii
56 Spikes 12–15 mm; perigynia flat or plano-convex, flat margin including wing 0.3–0.5 mm wide. Carex phaeocephala
57 Perigynia 2.9–4 mm from beak tip to achene, 0.4–0.5 mm thick; pistillate scales shorter than perigynia, exposing upper margins and beaks; beak tip similar in color to beak or sometimes gold-hyaline. Carex ebenea
57 Perigynia less than 2.9 mm from beak tip to achene or, if to 3 mm, then 0.5–0.8 mm thick and pistillate scales covering perigynia; beak tip white-hyaline. > 58
58 Perigynia thick-walled ± leathery, with metallic sheen. > 59
58 Perigynia thin-walled, not leathery, with or without metallic sheen. > 60
59 Spikes densely aggregated, individually indistinct, sometimes proximal 1–3 distant; proximal inflorescence internode 2–3(–4.5) mm; spike bases rounded. Carex subbracteata
59 Spikes usually distant to loosely aggregated, at least proximal 1–3 distinct; proximal inflorescence internode 2.5–7 mm; spike bases acute to attenuate. Carex gracilior
60 Perignyium beak with apex white-hyaline, abaxial suture white-hyaline. > 61
60 Perignyium beak with apex and abaxial suture similar in color to beak or gold- or brown-hyaline. > 64
61 Pistillate scales less than 3.7 mm; perigynia with glossy metallic sheen; proximal inflorescence internode 0.7–4.5(–9) mm. > 62
61 Pistillate scales at least 3.7 mm; perigynia without glossy metallic sheen; proximal inflorescence internode 4–14 mm. > 63
62 Perigynia 0.4–0.5 mm thick, wings dark, conspicuously contrasting with body color. Carex macloviana
62 Perigynia 0.5–0.7 mm thick, wings similar in color to body, at most dark-edged. Carex pachystachya
63 Perigynia 0.4–0.5 mm thick; 2d inflorescence internode usually 2– 5 mm; subalpine to alpine. Carex phaeocephala
63 Perigynia 0.5–0.8 mm thick; 2d inflorescence internode usually 4– 10 mm; lowlands to subalpine. Carex praticola
64 Achenes 1–1.6 mm; inflorescences appearing fine-textured. Carex subfusca
64 Achenes (1.3–)1.5–2 mm; inflorescences appearing rather coarse-textured. > 65
65 Spikes densely aggregated, individually indistinct; proximal 2 inflorescence internodes collectively less than 1/3 length of inflorescences. > 66
65 Spikes distant to loosely aggregated, individually distinct or, if ± densely aggregated; proximal 2 inflorescence internodes collectively more than 1/3 length of inflorescences. > 67
66 Perigynia green or straw colored to light brown (coppery); beak tip gold or brown. Carex harfordii
66 Perigynia gold or coppery to blackish; beak tip red-brown or black. Carex pachystachya
67 Perigynia biconvex to plano-convex, without metallic sheen, usually green to- ward beak, contrasting in color with pistillate scales. Carex preslii
67 Perigynia plano-convex, with metallic sheen, usually not green toward beak, ± similar in color to pistillate scales. Carex pachystachya