Jepson eFlora
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Key to Carex

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Key to Groups

1. Plant hairy at least in part (check sheaths, blades, perigynium)

2. Leaves hairy; perigynium hairy or glabrous ..... Group 1

2' Leaves glabrous; perigynium hairy ..... Group 2

1' Plant completely glabrous throughout

3. Inflorescence 1 terminal spikelet ..... Group 3

3' Inflorescence generally >= 2 spikelets

4. Stigmas 3; fruit 3-angled

5. Inflorescence bract sheath >= 6 mm ..... Group 4

5' Inflorescence bract sheath < 5 mm

6. Perigynium inflated at least near beak ..... Group 5

6' Perigynium not inflated ..... Group 6

4' Stigmas 2; fruit lenticular

7. Pistillate and staminate flowers on different stems (unisexual stems) ..... Group 7

7' Pistillate and staminate flowers on same stem (bisexual stems)

8. Terminal spikelet(s) generally staminate; lateral spikelets pistillate (rarely tips staminate) ..... Group 8

8' Terminal and lateral spikelets all a mix of staminate and pistillate flowers

9. Spikelets each with staminate flowers above pistillate flowers (often easiest to see in terminal spikelet; look for remnants of stamens) ..... Group 9

9' Spikelets each with pistillate flowers above staminate flowers

10. Perigynium not winged (occasionally thin-edged above); stem generally solid; cespitose or rhizomed ..... Group 10

10' Perigynium winged; stem hollow; cespitose ..... Group 11

Group 1: Sheaths and/or blades hairy

1. Plants dioecious

2. Spikelets 1–4; plant loosely cespitose; fruit << perigynium body ..... C. scabriuscula

2' Spikelet generally 1; plant rhizomed; fruit ± = perigynium body ..... C. scirpoidea subsp. pseudoscirpoidea

1' Plants monoecious

3. Leaf blades glabrous, sheaths hairy at least at mouth

4. Perigynium glabrous; leaves 1.5–23 mm wide

5. Longer teeth of perigynium beak 1.5–3.3 mm, curved ..... C. atherodes (2)

5' Longer teeth of perigynium beak < 0.5 mm, straight

6. Plant rhizomed; leaves 8–23 mm wide; perigynium abruptly narrowed to beak ..... C. amplifolia

6' Plant cespitose; leaves 1.5–5.5 mm wide; perigynium gradually narrowed to beak

7. Distal lateral spikelets arching or drooping, 0.7–3.5(–6) mm between perigynium at mid-spikelet; proximal staminate flower bract awns 0.5–5 mm; pistillate flower bracts, including awns, (2.2)3–4.8(–6.8) mm, awns (0–)0.5–2.2(–3.1) mm ..... C. cyrtostachya

7' Distal lateral spikelets erect or ascending, 0.3–0.6(–1.2) mm between perigynium at mid-spikelet; proximal staminate flower bract awns 0 (0.3–0.5 mm); pistillate flower bracts, including awns, 1.7–3.2(–3.7) mm, awns 0–0.3(–2) mm ..... C. mendocinensis (3)

4' Perigynium hairy; leaves 1.5–8 mm wide

8. Plant rhizomed; often in standing water --> see couplet 5

8' Plant cespitose; upland or damp ground, rarely in standing water

9. Pistillate flower bract face hairy; lowest inflorescence bract sheath < 5 mm; spikelets, upper 1/2 of perigynium dark purple; talus, 2600–3900 m ..... C. congdonii (2)

9' Pistillate flower bract face glabrous; lowest inflorescence bract sheath 20–30 mm; spikelets, perigynium green to gold or pale brown; moist ground, often on serpentine, 150–1600 m ..... C. mendocinensis (3)

3' Leaf blades hairy, sheaths hairy or glabrous

10. Plant long-rhizomed; sheath fronts occasionally fibrous

11. Perigynium sparse-hairy on main veins or glabrous; longer teeth of perigynium beak 1.5–3.3 mm ..... C. atherodes (2)

11' Perigynium dense-hairy; longer teeth of perigynium beak 0.2–1.4 mm

12. Perigynium gradually narrowed to long beak; fruit << perigynium body; leaf sheaths white, not red-dotted, not fibrous; mature spikelets 8–10 mm wide ..... C. sheldonii

12' Perigynium ± abruptly narrowed to beak; fruit ± = body; leaf sheaths often red-dotted, fibrous; mature spikelets 4–7 mm wide

13. Leaf blades inrolled to triangular-channeled, 0.7–2(2.2) mm wide, those of vegetative shoots especially prolonged into curled, thread-like tips; midvein of leaf, inflorescence bract a low, rounded, inconspicuous keel at least toward base ..... C. lasiocarpa

13' Leaf blades flat or folded into an M-shape except at base and near tip, (2)2.2–4.5(6) mm wide, not prolonged into thread-like tips; midvein of leaf, inflorescence bract a prominent, sharp keel ..... C. pellita

10' Plant cespitose to loosely so, forming clumps; sheath fronts not fibrous

14. Lowest inflorescence bract sheath < 5 mm; terminal spikelet staminate; not on serpentine

15. Perigynium glabrous, face strongly 5-veined; pistillate flower bracts glabrous; stem brown (red-brown) at base ..... C. whitneyi

15' Perigynium hairy, face faintly 0–10 veined; pistillate flower bracts hairy near tips; stem red to purple at base

16. Pistillate flower bracts dark purple with 1–5 pale brown, strong veins; spikelets dark; perigynium > pistillate flower bracts, purple on upper 1/2 of body, gradually narrowed above; talus, 2600–3900 m ..... C. congdonii (2)

16' Pistillate flower bracts with 1 weak vein in wide central green zone; spikelets light; perigynium < or > pistillate flower bracts, green to dark brown (dark purple) on upper 1/2 of body, generally abruptly narrowed above; moist or wet sites, 1200–2600 m ..... C. sartwelliana

14' Lowest inflorescence bract sheath > 5 mm; terminal spikelet staminate or staminate and pistillate; generally on serpentine

17. Perigynium generally glabrous (sparse-hairy toward tip); leaf blade glabrous or sparsely hairy at base; basal leaves 1.5–5.5 mm wide ..... C. mendocinensis (3)

17' Perigynium hairy; leaf blade hairy; basal leaves occasionally > 7 mm wide

18. Pistillate flower bracts obovate to wide-elliptic, red-brown or ± purple, midrib green; perigynium purple-splotched; on serpentine, < 600 m, North Coast, Klamath Ranges, Outer North Coast Ranges, n Central Coast (Marin, Santa Cruz cos.), San Francisco Bay Area, Outer South Coast Ranges ..... C. gynodynama

18' Pistillate flower bracts elliptic to elliptic-obovate, green or pale red-brown, midrib green; perigynium green or gold-green to pale brown, occasionally red-dotted but not purple-splotched; often on serpentine, 60–1200 m, North Coast Ranges (Mendocino, Lake cos.), Cascade Range, n&c Sierra Nevada ..... C. hirtissima

Group 2: Perigynium hairy

1. Flower stems all unisexual, either staminate or pistillate

2. Flower stems staminate

3. Flower stem base scaly, not fibrous; spikelets 1–4; anthers 2–2.8 mm ..... C. scabriuscula (2)

3' Flower stem base ± fibrous, scaly or not; spikelet 1; anthers 3.1–4.5 mm

4. Leaf sheath front occasionally hairy, not coarse-veined, fine-red-dotted; ligule occasionally longer than wide ..... C. scirpoidea subsp. pseudoscirpoidea (2)

4' Leaf sheath front glabrous, coarse-veined, generally not red-dotted; ligule wider than long ..... C. serpenticola (3)

2' Flower stems pistillate

5. Perigynium flat except over relatively small fruit, perigynium veins strong on lower 1/2 (obscure if dark purple) ..... C. scabriuscula (2)

5' Perigynium plump, filled by fruit, perigynium veins 0 or short, weak on lower 1/2

6. Spikelets generally 1 (2, overlapped), oblong-cylindric; mature stems stiffly erect ..... C. scirpoidea subsp. pseudoscirpoidea (2)

6' Spikelets 2–4, lowest generally well-separated or obvious, generally elliptic-ovate to ± spheric; mature stems weak, drooping ..... C. serpenticola (3)

1' Some or all flowering stems bisexual, with both staminate and pistillate flowers

7. Stigmas 4, warty, not plumose, at 15×; fruit base 4-angled; leaf sheath mouth V-shaped; leaves ± sickle-shaped — Klamath Ranges, North Coast Ranges ..... C. concinnoides

7' Stigmas 3, fine-plumose at 15×; fruit base 3-angled; leaf sheath mouth U-shaped; leaves straight (except Carex brevicaulis sickle-shaped)

8. Basal spikelets present

9. Perigynium with 12–20 strong veins at least to midbody; pistillate flower bracts generally prominently 3–5-veined

10. Leaves pale blue-green or glaucous; perigynium stalks ± = beaks; perigynium bodies barrel-shaped; leaves generally papillate abaxially at 40× ..... C. brainerdii

10' Leaves green, not glaucous; perigynium stalks 1.5–2 × beaks; perigynium bodies obovoid; leaves not papillate or papillate only on veins abaxially at 40×

11. Some basal spikelets on generally arching, long, slender stalk > 10 cm; perigynium <= 2.3 mm wide; perigynium stalks <= 2.2 mm; coastal moist forest, openings ..... C. globosa

11' All basal spikelets on stiffly erect stalks < 8 cm; perigynium <= 1.9 mm wide; perigynium stalks <= 1.6 mm; inland dry forest, savannah, chaparral ..... C. xerophila

9' Perigynium with 2 strong veins, veins otherwise 0 or faint; pistillate flower bracts prominently 1(3)-veined

12. Inflorescence bracts on taller (non-basal) stems inconspicuous, scale-like, < inflorescence; old leaves occasionally persisting as shredded fibrous tufts; perigynium 1.5–2.1 mm wide; coastal dunes, headlands, North Coast, Central Coast ..... C. brevicaulis

12' Inflorescence bracts on taller (non-basal) stems prominent, leaf-like, generally >= inflorescence; old leaves not persisting as shredded fibrous tufts; perigynium 1–1.7 mm wide; North Coast, Central Coast, and elsewhere

13. Perigynium 2.3–3.1 mm, beak 0.4–0.8 mm, teeth 0.1–0.2 mm; stems generally spreading or arching, ± smooth except near inflorescence; plant loosely cespitose; rhizomes slender ..... C. deflexa var. boottii (2)

13' Perigynium 3.1–4.5 mm, beak 0.7–1.7 mm, teeth 0.2–0.4 mm; stems generally ascending, scabrous; plant loosely to densely cespitose; rhizomes stout ..... C. rossii

8' Basal spikelets 0

14. Staminate spikelets 2–3

15. Stems 10–50 cm; dry uplands, Siskiyou Co. ..... C. halliana (2)

15' Stems 60–180 cm; wet soil, Siskiyou Co. and elsewhere

16. Plants cespitose (Carex spissa cespitose to rhizomed); perigynium sparse-hairy, sharp-3-angled or 2-edged, generally fine-red-dotted; springs, seeps, streambanks, generally not in standing water, often on serpentine; Central Coast, Outer South Coast Ranges, South Coast

17. Perigynium sharp-3-angled, lanceolate, gradually narrowed to long beak ± 2 mm; lateral spikelets with 15–45 perigynium; generally on serpentine; Outer South Coast Ranges (Monterey, San Luis Obispo cos.), Peninsular Ranges ..... C. obispoensis (2)

17' Perigynium often ± flat, 2-edged, or strongly inflated, but not 3-angled, obovoid, abruptly narrowed to beak ± 0.5 mm; lateral spikelets with 150–300 perigynium; on serpentine or not; Central Coast, South Coast ..... C. spissa

16' Plants rhizomed; perigynium dense-hairy, plump, not sharp-3-angled or 2-edged, green or dark-purple-splotched; often emergent in shallow water, not on serpentine; widespread

18. Leaf blades inrolled to triangular-channeled, 0.7–2(2.2) mm wide, those of vegetative shoots especially prolonged into curled, thread-like tips; midvein of leaf, inflorescence bract a low, rounded, inconspicuous keel at least toward base ..... C. lasiocarpa

18' Leaf blades flat or folded into an M-shape except at base and near tip, (2)2.2–4.5(6) mm wide, not prolonged into thread-like tips; midvein of leaf, inflorescence bract a prominent, sharp keel ..... C. pellita

14' Staminate spikelet 1 (except Carex triquetra, Carex obispoensis with 1–2 upper lateral spikelets occasionally staminate/pistillate, but not entirely staminate)

19. Spikelets 1, terminal ..... C. filifolia

20. Longest pistillate flower bracts (except awns) generally < 2.5 mm, generally << perigynium; perigynium body generally abruptly narrowed to beak 0–0.4 mm; fruit 1.6–2.4 mm ..... var. erostrata

20' Longest pistillate flower bracts (except awns) generally > 3 mm, generally >= perigynium; perigynium body ± gradually narrowed to beak 0.1–0.8 mm; fruit 2.2–3 mm ..... var. filifolia

19' Spikelets > 1, terminal and lateral

21. Lateral spikelets generally < 1 cm; mouth of leaf sheath fine-toothed

22. Rhizomes short, plants loosely cespitose; perigynium 1–1.4 mm wide ..... C. deflexa var. boottii (2)

22' Rhizomes elongate, plants generally scattered; perigynium 1.5–2.2 mm wide

23. Pistillate flower bracts, lower staminate flower bracts green, red, or purple with white margin 0.4–0.8 mm wide; terminal spikelet staminate on taller inflorescences; stems bisexual; High Cascade Range ..... C. inops subsp. inops

23' Pistillate flower bracts, lower staminate flower bracts dark purple with white margin 0.1–0.2 mm wide; terminal spikelet on taller inflorescences staminate, pistillate, or pistillate/staminate; stems unisexual or bisexual; Klamath Ranges ..... C. serpenticola (3)

21' Lateral spikelets generally > 1.5 cm; mouth of leaf sheath entire or fine-ciliate

24. Plant rhizomed; leaf blade smooth; often in pumice — Klamath Ranges, High Cascade Range ..... C. halliana (2)

24' Plant cespitose; leaf blade smooth, scabrous, or minute-papillate; not in pumice

25. Perigynium hairs obvious, not sparse

26. Perigynium lanceolate, ± gradually narrowed to beak ± 2 mm; generally on serpentine; Outer South Coast Ranges (Monterey, San Luis Obispo cos.), Peninsular Ranges ..... C. obispoensis (2)

26' Perigynium elliptic, abruptly narrowed to beak < 1 mm; not on serpentine; Central Coast, South Coast, s Channel Islands, Transverse Ranges, Peninsular Ranges ..... C. triquetra

25' Perigynium hairs 0 or occasionally inconspicuous, sparse

27. Spikelets <= 60 mm; perigynium, pistillate flower bract green to brown, occasionally red-marked; generally on serpentine ..... C. mendocinensis

27' Spikelets <= 32 mm; perigynium, pistillate flower bract red-brown to dark purple, or green, marked with red-brown to dark purple; generally not on serpentine

28. Peri, at least distally on faces, with sparse, spreading-ascending, short, stiff, stout hairs or bristles; flower bract midvein distal margin scabrous to ciliate ..... C. fissuricola

28' Perigynium faces generally glabrous or with sparse, spreading to appressed, generally long, soft, thin hairs; flower bract midvein, margin glabrous ..... C. luzulina

Group 3: Spikelet 1

1. Lowest pistillate flower bracts green, leaf-like, 1–15 cm, base clasping perigynium; perigynium with bristle-like axis inside

2. Upper stem round or blunt-3–angled, generally smooth toward tip; perigynium with 2 strong marginal veins, several faint veins; longest leaves much exceeded by inflorescence, blades inrolled or flat, 0.8–1.5 mm wide; plant cespitose ..... C. multicaulis

2' Upper stem sharp-3–angled, scabrous toward tip; perigynium with 2 strong marginal veins, generally 0 faint veins; longest leaves ± equaling inflorescence, blades flat, 1.5–3 mm wide; plant loosely cespitose ..... C. tompkinsii

1' Lowest pistillate flower bracts not green, not leaf-like, <= 1.5 cm, base clasping perigynium or not; perigynium with bristle-like axis inside or not

3. Perigynium body wide-elliptic to ± round

4. Perigynium 2–4.8 mm wide; generally some lower pistillate flower bracts 3- or 5-veined; dry soil ..... C. breweri

4' Perigynium 1.5–1.8 mm wide; lower pistillate flower bracts 1-veined; wet or seasonally wet soil

5. Stigmas 2; leaves green, <= 1 mm wide; peatland, moist alpine meadows ..... C. capitata

5' Stigmas 3; leaves ± glaucous, 2–5 mm wide; meadows ..... C. idahoa (2)

3' Perigynium body narrowly elliptic to oblanceolate

6. Perigynium green, tip blunt, beak 0

7. Perigynium obovoid, marginal veins 2, fine veins 0 ..... C. geyeri (2)

7' Perigynium elliptic to narrow-oblong-elliptic, with many fine veins ..... C. leptalea

6' Perigynium green or straw to dark purple, tip pointed or distinctly beaked

8. Perigynium 1–3 per stem, 4.9–7 mm; leaves evergreen ..... C. geyeri (2)

8' Perigynium 8–50 per stem, 2–5 mm; leaves deciduous

9. Mature perigynium gradually narrowed to ± long stalk and beak; perigynium narrow-elliptic, often ± ascending to spreading or reflexed; pistillate flower bracts shed before perigynium ..... C. nigricans

9' Mature perigynium abruptly narrowed to short stalk or beak or both; perigynium elliptic to obovate, ascending or erect; pistillate flower bracts persisting with perigynium

10. Leaves ± glaucous, flat, 2–5 mm wide; perigynium without bristle-like axis inside ..... C. idahoa (2)

10' Leaves green, not glaucous, inrolled or channeled, 0.4–1 mm wide; perigynium with bristle-like axis inside ..... C. subnigricans

Group 4: Stigmas 3; inflorescence bract sheath >= 6 mm

1. Plant rhizomed

2. Perigynium inflated; style persisting on fruit; stem base spongy-thickened; leaf sheaths, lower leaf blades with well-developed brickwork pattern of crosswalls ..... C. utriculata

2' Perigynium not inflated; style breaking off near fruit; stem base not spongy-thickened; leaf sheaths, lower leaf blades without well-developed brickwork pattern of crosswalls

3. Stigmas 2–3 (generally an even mix on a stem), ripe fruit lenticular or 3-angled; serpentine wetlands, Klamath Ranges ..... C. hassei

3' Stigmas 3, ripe achenes 3-angled; various (including serpentine) wetlands or meadows, Klamath Ranges and elsewhere

4. Perigynium beak distinct or indistinct, 0.5–1.5 mm; leaves green, not glaucous

5. Stem base red or purple; perigynium abruptly narrowed to distinct beak; lower leaves on flowering stems reduced to bladeless sheaths ..... C. californica

5' Stem base brown; perigynium gradually narrowed to indistinct beak; lower leaves on flowering stems well developed ..... C. luzulina (4)

4' Perigynium beak indistinct, < 0.5 mm; leaves glaucous

6. Perigynium beak bent to 1 side; perigynium obovate, veins generally strong; leaves flat or folded; serpentine fens; Klamath Ranges, Inner North Coast Ranges ..... C. klamathensis

6' Perigynium beak straight; perigynium elliptic, veins weak or 0; leaves channeled; coastal peatland, not on serpentine; North Coast (Mendocino Co.) ..... C. livida

1' Plant cespitose to loosely so (Carex spissa cespitose to rhizomed)

7. Perigynium beak teeth spreading, generally curved, 1.3–2.8 mm ..... C. comosa

7' Perigynium beak teeth 0 or erect, straight, < 1 mm

8. Terminal spikelet generally pistillate/staminate

9. Pistillate flower bracts white; perigynium 1.3–2.3 mm ..... C. tiogana (2)

9' Pistillate flower bracts red-brown or purple; perigynium 3–5.5 mm

10. Perigynium plump, 0.9–2 mm wide

11. Perigynium not papillate, ovate to lanceolate ..... C. luzulina (4)

11' Perigynium papillate, wide-elliptic to ovate ..... C. serratodens

10' Perigynium flat, 1.7–3.5 mm wide

12. Lateral spikelets pistillate, larger with < 50 perigynium ..... C. heteroneura

12' Lateral spikelets generally pistillate/staminate, larger with > 60 perigynium ..... C. mertensii

8' Terminal spikelet generally staminate or staminate/pistillate (pistillate/staminate)

13. Wider leaves 9–20 mm wide; stems often weak, leaning

14. Perigynium gradually narrowed to indistinct beak; spikelets erect or spreading

15. Perigynium 4.3–6.5 mm, 20–32-veined, not red-dotted; inflorescence bract sheaths inflated; fruit stems often prostrate; coastal forest, not on serpentine, < 900 m ..... C. hendersonii

15' Perigynium 2.5–4.3 mm, finely 8–10-veined, occasionally red-dotted; inflorescence bract sheaths not inflated; fruit stems erect or ascending; openings, mixed-evergreen forest, disturbed wet places, often on serpentine, 60–1200 m ..... C. hirtissima

14' Perigynium abruptly narrowed to distinct beak; spikelets erect to spreading or drooping

16. Spikelets 1–3 cm, dark purple; perigynium < 30, margins flat; leaves green; 1900–3100 m ..... C. luzulifolia (2)

16' Spikelets 3–20 cm, green; perigynium generally > 75, margins not flat; leaves blue-green, at least when young; < 1200 m

17. Perigynium body elliptic, 1.1–1.5 mm wide; stem base red to purple; pistillate spikelets 5–8 mm wide ..... C. pendula

17' Perigynium body obovate, 1.5–2.5 mm wide; stem base brown; pistillate spikelets 7–12 mm wide ..... C. spissa

13' Wider leaves generally 1–8 mm wide; stems erect or leaning

18. Spikelets ± sessile, erect; inflorescence bracts ± stiff, ascending or spreading; perigynium green to ± yellow or brown

19. Perigynium body lanceolate, gradually narrowed to indistinct beak ..... C. lemmonii (2)

19' Perigynium body elliptic to ovate or obovate, abruptly narrowed to distinct beak ..... C. viridula subsp. viridula

18' Spikelets stalked, erect or arching to drooping; inflorescence bracts ± weak, spreading; perigynium white, green, brown, red-brown, or purple

20. Perigynium beak distinct, <= 0.5 mm, or indistinct

21. Perigynium 1.3–2.3 mm, 0.4–0.9 mm wide; pistillate flower bract white ..... C. tiogana (2)

21' Perigynium 3–5.5 mm, 0.9–2 mm wide; pistillate flower bract red-brown or dark purple

22. Perigynium body ovate to lanceolate, gradually narrowed to indistinct beak ..... C. luzulina (4)

22' Perigynium body obovate to wide-elliptic, abruptly narrowed to distinct beak ..... C. raynoldsii

20' Perigynium beak distinct, generally > 0.5 mm

23. Pistillate spikelets (15)20–60 mm, linear; perigynium beak ciliate on inner side of teeth

24. Distal lateral spikelets arching or drooping, 0.7–3.5(–6) mm between perigynium at mid-spikelet; proximal staminate flower bract awns 0.5–5 mm; pistillate flower bracts, including awns, (2.2)3–4.8(–6.8) mm, awns (0–)0.5–2.2(–3.1) mm ..... C. cyrtostachya

24' Distal lateral spikelets erect or ascending, 0.3–0.6(–1.2) mm between perigynium at mid-spikelet; proximal staminate flower bract awns 0 (0.3–0.5 mm); pistillate flower bracts, including awns, 1.7–3.2(–3.7) mm, awns 0–0.3(–2) mm ..... C. mendocinensis

23' Pistillate spikelets generally <= 20 mm, oblong; perigynium beak generally not ciliate on inner side of teeth, but beak margins and outer side of teeth generally with spreading, stiff bristles

25. Perigynium faces, at least near beak, with sparse, spreading-ascending, short, stiff, bristles; pistillate flower bract margins ciliate distally ..... C. fissuricola

25' Perigynium faces generally glabrous (or with sparse, weak hairs); pistillate flower bract margins glabrous

26. Perigynium flat margin > 1/2 fruit width; perigynium 1.7–2.5 mm wide; inflorescence bract sheath expanded toward shallow-U-shaped mouth (1.8)2–3 mm wide ..... C. luzulifolia (2)

26' Perigynium flat margin 0 or < 1/2 fruit width; perigynium 0.9–2 mm wide; inflorescence bract sheath not (or ±) expanded toward shallow Y- or V-shaped mouth 0.6–2 mm wide

27. Perigynium beak tip to fruit tip < 1.5 mm; lowest spikelet stalk generally exserted < 10 mm; pistillate flower bracts white, green, gold, or red-brown to dark purple, margin white ..... C. lemmonii (2)

27' Perigynium beak tip to fruit tip >= 1.5 mm; lowest spikelet stalk exserted > 10 (> 5) mm; pistillate flower bracts generally red-brown to dark purple ..... C. luzulina (4)

Group 5: Stigmas 3; inflorescence bract sheath < 6 mm; perigynium inflated at least near beak

1. Lower lateral spikelets nodding on drooping stalks

2. Perigynium strongly 7–11-veined, beak teeth without eroded tips, 0.3–2.8 mm

3. Perigynium beak teeth spreading or strongly curved, 1.3–2.8 mm, not prickle-like; stem base brown ..... C. comosa

3' Perigynium beak teeth erect, straight, 0.3–0.9 mm, prickle-like; stem base red-purple ..... C. hystericina

2' Perigynium weakly 0–7-veined, beak teeth with eroded tips or < 0.5 mm

4. Perigynium obovate; leaf margins very sharply scabrous ..... C. spissa (2)

4' Perigynium elliptic to ovate; leaf margins smooth to ± serrate

5. Plant rhizomed; perigynium beak 0.7–1.2 mm ..... C. amplifolia

5' Plant cespitose; perigynium beak 0.5 mm ..... C. pendula

1' Lower lateral spikelets generally erect, stalks sometimes 0

6. Lateral spikelets 4–20 mm; perigynium 1.8–4.5 mm

7. Pistillate flower bracts dark purple or black; perigynium 1.6–2.1 mm wide ..... C. raynoldsii

7' Pistillate flower bracts green to rusty; perigynium 0.8–1.6 mm wide ..... C. viridula subsp. viridula

6' Lateral spikelets 20–100 mm; perigynium 3.6–12.7 mm

8. Perigynium widest above middle, weakly veined; leaf margins very sharply scabrous; young leaves blue-green ..... C. spissa (2)

8' Perigynium widest below middle, strongly veined; leaf margins entire or weakly serrate; young leaves green

9. Plant long-rhizomed; stem base spongy-thickened, brown or red-tinged, crosswalls between veins many, well developed, yielding brick-like pattern, sheaths generally not fibrous; ligule length generally < width on lower leaves; widest leaves to 15 mm wide ..... C. utriculata

9' Plant ± cespitose; stem base not spongy-thickened, generally red- or purple-tinged, crosswalls between veins generally few, weakly developed, not yielding brick-like pattern; sheaths often fibrous; ligule length > width on lower leaves; widest leaves to 6.5 mm wide

10. Larger perigynium 7.5–12.7 mm, length 3.4–7.4 × width, tip gradually narrowed to an indistinct beak; < 1800 m ..... C. exsiccata

10' Larger perigynium 3.6–8.2 mm, length generally 2–3.5 × width, tip ± abruptly narrowed to ± distinct beak; < 3300 m ..... C. vesicaria

Group 6: Stigmas 3; inflorescence bract sheath < 6 mm; perigynium not inflated

1. Perigynium beak teeth curved, 1.3–2.8 mm ..... C. comosa

1' Perigynium beak teeth 0 or inconspicuous, straight, 0–1 mm

2. Leaves 8–23 mm wide; lateral spikelets often with > 100 perigynium

3. Stem brown at base; upper 2–4 spikelets staminate; sheaths, perigynium red-dotted ..... C. spissa

3' Stem ± red or ± purple at base; uppermost spikelet staminate; sheaths, perigynium not red-dotted

4. Plant rhizomed; perigynium beak 0.7–1.1 mm ..... C. amplifolia

4' Plant cespitose; perigynium beak 0.5 mm ..... C. pendula

2' Leaves < 8.5 mm wide; lateral spikelets with < 70 perigynium

5. Plant long-rhizomed; perigynium beak 0–0.5 mm; leaves glaucous; perigynium papillate

6. Perigynium abruptly narrowed to distinct beak

7. Perigynium beak straight, beak, upper body often minute-serrate or bristly; moist mountain meadows over dolomite, 2800–3400 m, White and Inyo Mountains (White Mtns) ..... C. idahoa (3)

7' Perigynium beak bent to side, beak, upper body not minute-serrate, not bristly; serpentine fens, 450–900 m, Klamath Ranges, Inner North Coast Ranges ..... C. klamathensis

6' Perigynium tapered to indistinct beak

8. Spikelets nodding; roots with dense felt-like hairs ..... C. limosa

8' Spikelets erect or ascending; roots without dense felt-like hairs

9. Pistillate flower bracts prominently awned; sheaths fibrous; terminal spikelet pistillate/staminate ..... C. buxbaumii

9' Pistillate flower bracts awnless; sheaths not fibrous; terminal spikelet staminate ..... C. livida

5' Plant cespitose to loosely so; perigynium beak < to > 0.5 mm; leaves green or glaucous; perigynium papillate or not

10. Spikelets green to gold, pistillate flower bracts without dark purple or black

11. Perigynium 1.3–2 mm, beak 0.2–0.4 mm; pistillate flower bracts blunt or mucronate; 3100–3350 m, c High Sierra Nevada (Mono Co.) ..... C. tiogana

11' Perigynium 4.5–7.3 mm, beak 0 or 1.9–2.8 mm; pistillate flower bracts long-awned; < 1800 m, Klamath Ranges, Sierra Nevada

12. Terminal spikelet staminate; lateral spikelets 2–4, generally nodding, dense; perigynium rounded, > 25, ribs 3, veins 13–21, beak 1.9–2.8 mm, teeth prominent, 0.3–0.9 mm ..... C. hystericina

12' Terminal spikelet staminate flowers above pistillate; lateral spikelet 1, erect, not dense; perigynium 3-angled, 1–5, ribs 3, veins 0, beak 0, teeth 0 ..... C. tompkinsii

10' Spikelets darker than green to gold, pistillate flower bracts at least partly dark brown to dark purple or black

13. Terminal spikelet staminate (some species variable, keying here or at 13')

14. Perigynium ascending, <= 1/2 filled by fruit; lower spikelets often nodding on drooping stalks ..... C. spectabilis

14' Perigynium spreading, > 1/2 filled by fruit; lower spikelets generally erect

15. Perigynium body ovate to widely elliptic, beak 0.3–1 mm, teeth generally bristly, 0.2–0.5 mm; < 1800 m, often on serpentine ..... C. serratodens (2)

15' Perigynium body elliptic to obovate, beak 0.1–0.5 mm, teeth 0 or smooth to bristly, < 0.2 mm; 1800–3200 m, not on serpentine

16. Lateral spikelets < terminal; perigynium 2–3 mm ..... C. idahoa (3)

16' Lateral spikelets >= terminal; perigynium 3.5–4.5 mm ..... C. raynoldsii

13' Terminal spikelet pistillate or pistillate/staminate (or staminate/pistillate/staminate in some Carex helleri)

17. Perigynium flat, < 1/2 filled by fruit, generally not papillate (± papillate near beak)

18. Lateral spikelets spreading or drooping, often > 2 cm, generally pistillate/staminate, basal flowers with remnant filaments ..... C. mertensii

18' Lateral spikelets generally erect or ascending, generally < 2 cm, generally pistillate

19. Lower pistillate flower bracts acuminate, awns generally 0.5–2 mm; perigynium elliptic to obovate; stem 5–40 cm ..... C. helleri

19' Lower pistillate flower bracts acute to acuminate, awns < 0.5 mm or generally 0; perigynium ovate to ± round or obovate; stem 25–100 cm ..... C. heteroneura

17' Perigynium plump, > 1/2 filled by fruit, papillate or not

20. Perigynium ovate to widely elliptic, generally 3–5 mm ..... C. serratodens (2)

20' Perigynium elliptic to obovate, generally 2–3 mm

21. Perigynium green to olive, obvious, strongly contrasting with, not hidden by shorter, darker pistillate flower bracts ..... C. stevenii

21' Perigynium yellow to dark brown to dark purple, hidden by or not contrasting with pistillate flower bracts

22. Perigynium upper body, beak not minute-serrate or bristly; pistillate flower bracts oblong or lanceolate to widely elliptic, tips not bristly ..... C. orestera

22' Perigynium upper body, beak minute-serrate or bristly; pistillate flower bracts obovate to widely elliptic, tips or awns bristly or not ..... C. idahoa (3)

Group 7: Spikelets 2+; stigmas 2; stems generally unisexual

1. Stems staminate or mostly so

2. Plant cespitose to loosely so (Carex alma cespitose to rhizomed); spikelets >= 1 per lower node or branch; leaf sheath front red-dotted or not

3. Leaf sheath front not red-dotted; anther tips acute, awn 0 ..... C. infirminervia (2)

3' Leaf sheath front red-dotted; anther tips with bristle-like awn <= 0.3 mm

4. Leaf sheath front not cross-wrinkled, colorless at mouth, rim not thick or dark, generally with contraligule ..... C. alma (2)

4' Leaf sheath front occasionally cross-wrinkled, copper or ± purple at mouth, rim often thick or dark, without contraligule ..... C. cusickii (2)

2' Plant rhizomed; spikelets generally 1 per node or branch; leaf sheath front generally not red-dotted

5. Stem angles smooth near tip; rhizomes 0.6–1.9 mm thick

6. Anther awns 0.2–1 mm, bristly at 30×; leaf blades 1–3.5 mm wide; inflorescence 12–45 mm ..... C. douglasii (2)

6' Anther awns < 0.1 mm, smooth to warty at 30×; leaf blades < 1.5 mm wide; inflorescence <= 20 mm ..... C. duriuscula (2)

5' Stem angles ± scabrous near tip; rhizomes 1.5–5 mm thick

7. Longest anther awns 0.2–0.4 mm, filaments generally included; stem generally < 40 cm; coastal, islands ..... C. pansa (2)

7' Longest anther awns 0.1–0.2 mm, filaments exserted; stem 20–75 cm; coastal or inland

8. Anther awns generally hairy at 20×; leaf sheath mouth occasionally with dark or ± thick rim; leaf blades 1.5–3 mm wide ..... C. praegracilis (2)

8' Anther awns glabrous (warty) at 20×; leaf sheath mouth with or without dark stripe, generally without thick rim; leaf blades 2–5 mm wide ..... C. simulata (2)

1' Stems pistillate or mostly so

9. Plant cespitose (Carex alma cespitose to rhizomed)

10. Leaf sheath front copper or ± purple at mouth, often with thick or dark rim, mouth generally concave or truncate ..... C. cusickii (2)

10' Leaf sheath front colorless at mouth, without thick or dark rim, mouth concave to convex

11. Leaf sheath front red-dotted; perigynium ovate to triangular-ovate; inflorescence a dense panicle of spikelets, spikelets generally several per lower node, or lower node long-branched with 3+ spikelets ..... C. alma (2)

11' Leaf sheath front not red-dotted; perigynium narrow-lanceolate; inflorescence a raceme of spikelets, spikelets 1 per node ..... C. infirminervia (2)

9' Plant rhizomed

12. Upper stem smooth on angles; rhizomes 0.6–1.8 mm thick; shoots often 2–several in small clusters, 0 at many nodes

13. Pistillate flower bracts 4.3–7.5 mm, pale brown to ± white; perigynium beak 0.9–1.9 mm; spikelets generally unisexual; anthers 2.5–3.9 mm, tip 0.2–1 mm, bristly at 30× ..... C. douglasii (2)

13' Pistillate flower bracts 2.4–4.1 mm, red-brown; perigynium beak 0.3–0.9 mm; spikelets occasionally with staminate flowers above pistillate (as in Group 9); anthers 1.4–3 mm, awn < 0.1 mm, smooth to warty at 30× ..... C. duriuscula (2)

12' Upper stem ± scabrous on angles; rhizomes 1.5–5 mm thick; shoots generally 1 every few nodes

14. Perigynium beak 0.25–0.5 mm; contraligule 0.3–1.6 mm; anthers occasionally present, tip smooth to warty at 30× ..... C. simulata (2)

14' Perigynium beak 0.5–1.5 mm; contraligule 0; anthers occasionally present, tip bristly-hairy at 30×

15. Pistillate flower bracts, base of spikelet bracts dark brown or purple-brown, generally shiny, darker than perigynium; pistillate inflorescence not elongate, ovate to elliptic; coastal, islands ..... C. pansa (2)

15' Pistillate flower bracts, base of spikelet bracts pale brown to pale red-brown, ± dull, lighter than perigynium; pistillate inflorescence elongate, generally oblong-elliptic; generally inland ..... C. praegracilis (2)

Group 8: Stigmas 2, terminal spikelets generally staminate, lateral generally pistillate, rarely staminate-tipped

1. Perigynium fleshy, plump, often dense-papillate, tip blunt or with beak <= 0.3 mm; sheath of inflorescence bract generally > 4 mm; plants long-rhizomed

2. Mature perigynium, just before dropping, bright orange (green to white when immature, as in many herbarium specimens), ± spheric, ± spreading; pistillate flower bracts spreading, often falling before perigynium; ripe perigynium smooth (often papillate when immature)..... C. aurea

2' Mature perigynium, just before dropping, green to white, occasionally purple- or red-brown-marked, elliptic to elliptic-obovate, ascending; pistillate flower bracts ascending, generally ± persistent with perigynium; ripe perigynium dense-papillate at 10×

3. Upper 1/2 of perigynium generally green or white, ± abruptly rounded, blunt, or only slightly narrowed, red-brown generally only on small, occasionally bent beak, if present; lower staminate flower bracts blunt or short-awned, generally < 4 mm, not like inflorescence bract; spikelets 1 per lower node ..... C. hassei

3' Upper 1/2 of perigynium red-brown- or purple-splotched, gradually narrowed to tip or short straight beak; lower staminate flower bracts generally long-awned, >= 4.5 mm, like inflorescence bract; spikelets occasionally > 1 per lower node ..... C. saliniformis

1' Perigynium not fleshy, ± flat, papillate or not, tip distinctly beaked < or > 0.3 mm; sheath of inflorescence bract generally < 2 mm; plants long-rhizomed or cespitose

4. Plant cespitose; perigynium veined

5. Leaf sheath fronts fibrous; lower sheaths scabrous, red-brown to shiny dark brown

6. Stem 30–70 cm, < 1 cm wide at base; staminate spikelets 1–2, terminal < 5 cm; perigynium purple-splotched on upper 2/3; below high water mark on rocky streams ..... C. nudata

6' Stem 75–150 cm, ± 1 cm wide at base; staminate spikelets 2–7, terminal generally > 5 cm; perigynium red-spotted, generally more densely so toward base; creekbanks, wet meadows, swamps ..... C. schottii

5' Leaf sheath fronts not fibrous; lower sheaths glabrous, dull light brown ..... C. lenticularis

7. Lower spikelets 4–6 mm wide; perigynium stalks 0.4–0.7 mm; lower spikelets crowded, overlapping; perigynium = pistillate flower bracts; North Coast, < 20 m ..... var. limnophila

7' Lower spikelets generally 3–4 mm wide; perigynium stalks 0.1–0.5 mm; lower spikelets generally more separated; perigynium > pistillate flower bracts; Central Coast, San Francisco Bay Area or montane, < 3000 m

8. Upper 1/2 of perigynium purple-dotted, abaxially 1–3-veined, beak generally purple; perigynium stalks 0.1–0.2 mm ..... var. impressa

8' Upper 1/2 of perigynium generally green, abaxially generally 5–7-veined, beak generally green, tip purple; perigynium stalks 0.2–0.5 mm ..... var. lipocarpa

4' Plant rhizomed; perigynium veined or not

9. Leaf sheath fronts generally fibrous; lower sheaths generally scabrous

10. Perigynium ± soft, thin

11. Bladeless sheaths present on lower stem; perigynium 2.2–3.1 mm, 1.2–2 mm wide, weakly 1–3-veined adaxially on lower 1/2 ..... C. angustata

11' Bladeless sheaths 0 on lower stem; perigynium 3–4 mm, 2–2.2 mm wide, strongly 3–7-veined abaxially, adaxially ..... C. senta

10' Perigynium ± tough, thick

12. Perigynium generally red-spotted, faintly veined, dull, beak teeth bristly; pistillate flower bract awns bristly; fruit 0 or lenticular, not indented ..... C. barbarae (2)

12' Perigynium generally not red-spotted, not veined, shiny, beak teeth 0 or minute, not bristly; pistillate flower bract awns generally entire; fruit generally indented on 1–2 sides, like a bent beer can ..... C. obnupta

9' Leaf sheath fronts not fibrous (generally fibrous in Carex barbarae); lower sheaths generally not scabrous

13. Spikelets drooping or nodding (generally erect when immature)

14. Longest spikelets 1.8–5 cm; fruit often indented on 1–2 sides, like a bent beer can; coastal salt marshes, freshwater intertidal zones ..... C. lyngbyei

14' Longest spikelets 4.55–11.5 cm; fruit not indented; coastal or inland, freshwater ..... C. aquatilis var. dives

13' Spikelets generally erect or ascending

15. Mature perigynium faces veined, walls tough or thick

16. Leaves green, generally not glaucous, sheath front red-dotted, generally dark copper or purple near tip, lower generally fibrous ..... C. barbarae (2)

16' Leaves generally blue-green, ± glaucous, sheath fronts generally white, occasionally sparse-red-dotted or ± coppery, lower not fibrous ..... C. nebrascensis

15' Mature perigynium faces not veined, walls delicate or thin

17. Leaf sheaths red-dotted or white; inflorescence bract generally > inflorescence; flower stem base spongy-thickened ..... C. aquatilis var. aquatilis

17' Leaf sheaths brown- or purple-dotted; inflorescence bract < inflorescence; flower stem base thin, not spongy-thickened ..... C. scopulorum var. bracteosa

Group 9: Stigmas 2; spikelets with staminate flowers above pistillate flowers

1. Plants rhizomed (loosely cespitose)

2. Inflorescence ovoid to oblong, open to dense; lowest spikelets generally obvious at arm's length

3. Inflorescence 3–4 mm wide; lateral spikelets with 1–3 perigynium ..... C. disperma

3' Inflorescence > 5 mm wide; lateral spikelets with > 3 perigynium

4. Perigynium bulging, marginal veins occasionally not visible abaxially; pistillate flower bracts often with awns > 1 mm, the bracts covering perigynium ..... C. tumulicola (2)

4' Perigynium not bulging, marginal veins visible abaxially; pistillate flower bracts with awns 0 or < 1 mm, the bracts < or > perigynium, covering perigynium or not ..... Group 7, couplet 12

2' Inflorescence spheric to ovoid, dense; lowest spikelets not obvious at arm's length

5. Spikelets generally pistillate ..... Group 7, couplet 12

5' Spikelets staminate/pistillate

6. Leaves inrolled, ± = stem, 0.5–1.5 mm wide; stem curved; perigynium ± not inflated, > pistillate flower bracts, beak indistinct, 0.4–0.9 mm; anthers 0.9–1.4 mm ..... C. incurviformis

6' Leaves flat, < stem, (1.5)2–3.5(4) mm wide; stem straight; perigynium not inflated, ± = pistillate flower bracts, beak distinct, 0.9–1.5 mm; anthers 1.5–2.8 mm ..... C. vernacula

1' Plants cespitose to loosely so

7. Inflorescence branched, lower nodes or branches generally with > 1 spikelet; spikelets often > 10

8. Leaf sheath faces red-dotted

9. Perigynium pale to medium brown

10. Peri, beak, pistillate flower bract dull yellow-brown to medium- or red-brown; pistillate flower bract awns 0.5–2 mm; perigynium adaxial veins 0–5, abaxial 3–7; inflorescence often continuous, obvious bracts generally 0–few; flowering stems generally longer than leaves ..... C. densa

10' Peri, beak, pistillate flower bract dull yellow-green to pale gray-brown; pistillate flower bract awns to 3 mm; perigynium adaxial veins 0, abaxial 0–3; inflorescence often interrupted, obvious bracts often > few; flowering stems generally < leaves ..... C. vulpinoidea

9' Perigynium dark brown to black

11. Leaf sheath faces widely dark or coppery at top ..... C. cusickii

11' Leaf sheaths faces pale, not dark or coppery at top (narrowly copper-margined)

12. Perigynium 3–4.5 mm, 1.4–2.1 mm wide, beak 1–1.5 mm fruit 1–1.3 mm wide ..... C. alma

12' Perigynium 2–2.9 mm, 0.9–1.4 mm wide, beak 0.9–1.1 mm; fruit 0.7–1 mm wide ..... C. diandra

8' Leaf sheath faces white, not red-dotted

13. Perigynium widest near base, gradually narrowed to indistinct beak, length > 2 × width; sheath faces generally cross-wrinkled

14. Stem not winged, mid-stem generally <= 1.5 mm wide, not easily compressed between fingers; lower inflorescence branches < 1 cm ..... C. neurophora (2)

14' Stem wide-3-winged, mid-stem generally 2.5–7 mm wide, easily compressed between fingers; lower inflorescence branches generally 1–3+ cm ..... C. stipata var. stipata

13' Perigynium generally widest near middle, ± abruptly narrowed to distinct beak, length generally < 2 × width; sheath faces cross-wrinkled or not

15. Inflorescence open, lowest internode generally 2+ × lowest spikelet ..... C. divulsa subsp. divulsa (2)

15' Inflorescence dense, lowest internode < lowest spikelet (see couplet 12)

7' Inflorescence not branched, lower nodes with 1 spikelet; spikelets generally < 10

16. Perigynium widest near base, gradually narrowed to indistinct beak

17. Perigynium beak pale or green; introduced weeds at low elevations ..... C. texensis

17A. Spikelets densely clustered, indistinct at arm's length; inflorescence ovate; perigynium ovate ..... [C. leavenworthii]

17A' Spikelets loosely clustered, at least lowest spikelets distinct at arm's length; inflorescence narrow-oblong; perigynium lanceolate ..... C. texensis

17' Perigynium beak dark brown; native, often montane

18. Leaf sheath front generally cross-wrinkled; perigynium beak serrate at least on 1 side ..... C. neurophora (2)

18' Leaf sheath front not cross-wrinkled; perigynium beak entire

19. Perigynium adaxial veins 5–7; lower leaves generally overlapped and hiding sheaths; sheath mouth without thick rim ..... C. jonesii

19' Perigynium adaxial veins 7–12; lower leaves generally not overlapped and hiding sheaths; sheath mouth generally with thick rim ..... C. nervina

16' Perigynium widest near middle, often abruptly narrowed to distinct beak

20. Perigynium pale green or light brown; perigynium > pistillate flower bracts, easily visible

21. Inflorescence lowest internode generally 2+ × lowest spikelet ..... C. divulsa subsp. divulsa (2)

21' Inflorescence lowest internode <= lowest spikelet ..... C. vallicola

20' Perigynium center brown or copper, margins generally contrasting pale or green; perigynium >= pistillate flower bracts, often obscured

22. Inflorescence ovoid or spheric, 0.8–2 cm, 6–15 mm wide; lower spikelets generally not distinct ..... C. hoodii

22' Inflorescence oblong, 1.5–5 cm, 6–10 mm wide; lower spikelets ± distinct

23. Perigynium ascending to spreading, beak 0.6–1.3 mm; pistillate flower bracts 3.4–4 mm, 1.6–2 mm wide; lower bracts generally < spikelets, inflorescence ..... C. occidentalis

23' Perigynium erect, beak 1.2–3 mm; pistillate flower bracts 4–5.2 mm, 2–2.8 mm wide; lower bracts > spikelets, often > inflorescence ..... C. tumulicola (2)

Group 10: Stigmas 2; spikelets with pistillate flowers above staminate flowers; perigynium not winged; stems generally solid

1. Inflorescence bracts >> inflorescence; plant rhizomed; < 100 m ..... C. inversa

1' Inflorescence bracts generally < inflorescence; plant cespitose to loosely so; generally < 3500 m

2. Perigynium spreading or reflexed, beak obvious, spikelet outline jagged at arm's length

3. Staminate flower bracts inconspicuous in wide terminal spikelet

4. Pistillate flower bracts green, white, or light brown, spikelets green or pale brown; inflorescence oblong, elliptic, or lanceolate, >= 1.5 cm ..... C. arcta (2)

4' Pistillate flower bracts ± black, spikelets dark; inflorescence ovoid, <= 1.5 cm ..... C. illota

3' Staminate flower bracts obvious at narrowed base of terminal spikelet

5. Perigynium ascending to spreading, beak 15–40% perigynium length, perigynium attached at base ..... C. laeviculmis (2)

5' Perigynium widely spreading or reflexed, beak generally 20–85% perigynium length, perigynium attached near base abaxially

6. Lower perigynium in spikelet ± abruptly narrowed to short beak, margin with slight bulge or shoulder; beak 0.4–0.95, 18–44% length of body, perigynium generally 1.9–3.3 mm, length 1–2(2.2) × width ..... C. interior

6' Lower perigynium in spikelet more gradually narrowed to longer beak, margin without bulge or shoulder; beak 0.95–2 mm, 35–86% length of body, perigynium generally 2.9–4.75 mm, length 1.7–3.6 × width ..... C. echinata

7. Perigynium generally 2.9–4 mm, veins generally 0 over fruit adaxially; widest leaves generally 0.7–2.7 mm wide; inflorescence open to dense; Klamath Ranges, Outer North Coast Ranges, High Cascade Range, High Sierra Nevada, San Bernardino Mountains, < 3200 m ..... subsp. echinata

7' Perigynium generally 3.5–4.75 mm, veins 2–12 over fruit adaxially; widest leaves generally 1.7–3.8 mm wide; inflorescence dense; North Coast, Central Coast, < 200 m ..... subsp. phyllomanica

2' Perigynium ascending or beak inconspicuous, spikelet outline generally smooth at arm's length

8. Perigynium beak 0–0.5 mm; perigynium widest near middle

9. Perigynium fleshy; terminal spikelet generally obviously staminate at base, some terminal spikelets entirely staminate (see Group 8, couplet 2)

9' Perigynium not fleshy; terminal spikelet inconspicuously staminate at base, not entirely staminate

10. Perigynium beak abaxial flap pale, non-contrasting, not reaching to just below base of beak; stem generally erect, (10)30–90 cm ..... C. canescens subsp. canescens

10' Perigynium beak abaxial flap dark, contrasting, reaching to just below base of beak; stems generally leaning at 45° angle, 10–30 cm ..... C. praeceptorum

8' Perigynium beak generally 0.5–2.5 mm; perigynium widest below middle or near base

11. Inflorescence straight; spikelets clustered, lowest > lowest internode ..... C. arcta (2)

11' Inflorescence generally bent at lowest spikelet; spikelets separated, lowest generally < lowest internode

12. Perigynium beak 15–38% perigynium length (beak measured from fruit top, on perigynium from middle of spikelet)

13. Perigynium ascending or spreading, 2.3–3.7 mm, beak occasionally recurved; leaves 0.9–2.3 mm wide ..... C. laeviculmis (2)

13' Perigynium erect or ascending, 2.8–4.5 mm, beak not recurved; leaves 2.4–5.9 mm wide ..... C. leptopoda

12' Perigynium beak 39–53% perigynium length (beak measured from fruit top, on perigynium from middle of spikelet)

14. Perigynium beak teeth prominent, 0.2–1 mm; mid-stem glabrous or ± scabrous at 20× ..... C. bolanderi

14' Perigynium beak teeth not prominent, 0–0.2(0.4) mm; mid-stem papillate at 20× ..... C. infirminervia

Group 11: (sect. Ovales) Stigmas 2; spikelets with pistillate flowers above staminate; perigynium winged; stem hollow. Inflorescence bracts generally elongate on first flush of growth of some species, but other species sporadically produce elongate inflorescence bracts on late season shoots (e.g., C. fracta, C. specifica, C. subfusca). Late season shoots often with atypically elongate or compact inflorescence, and/or atypically shaped perigynium. Perigynium beak shape variable in some species (e.g., C. fracta, C. preslii, C. subfusca), ± uniform, important in others, e.g., C. specifica (see illustration), with beak margin either ± flat and serrate or ± so, except tip entire 0–0.3 mm, or e.g., C. abrupta (see illustration), beak tips ± cylindric, tip entire for >= 0.4 mm. [Note: For keying, use subbasal perigynium in mature spikelets from first flush of growth; avoid perigynium from upper 1/2 of spikelet, they are narrow and not diagnostic; similarly basal-most perigynium are occasionally malformed; use ripe perigynium, immature perigynium generally do not show critical ventral veins]

1. Leaf sheath front green ± to top, white-translucent triangular area extending < 6 mm below top ..... Group 11A

1' Leaf sheath front with extensive white-translucent zone extending > 10 mm below top

2. Contraligule 3–13 mm ..... Group 11B

2' Contraligule 0–2 mm

3. Perigynium margin entire and marginal wings 0 or < 0.2 mm wide ..... Group 11C

3' Perigynium margin minute-serrate, especially upper body or beak base or marginal wings generally > 0.2 mm wide

4. Pistillate flower bracts uniformly covering and ± obscuring perigynium; perigynium generally with strong abaxial veins ..... Group 11D

4' Pistillate flower bracts < or narrower than perigynium, perigynium easily visible; perigynium with strong abaxial veins or not

5. Larger perigynium 6–9.3 mm ..... Group 11E

5' Larger perigynium < 6 mm

6. Inflorescence bract obvious, > inflorescence ..... Group 11F

6' Inflorescence bract inconspicuous, < inflorescence

7. Perigynium beak tip broadly winged and flattened, minute-serrate throughout or ± so (cylindric entire tip <= 0.3 mm), generally pale or only slightly darkened ..... Group 11G

7' Perigynium beak tip cylindric, entire >= 0.4 mm, often darkened or ± black ..... Group 11H

Group 11A: Leaf sheath front green ± to top

1. Perigynium gradually narrowed to indistinct beak, generally lanceolate; pistillate flower bract tip acuminate to short-awned ..... C. scoparia var. scoparia

1' Perigynium abruptly narrowed to distinct beak, ovate to ± round to obovate or widely elliptic; pistillate flower bract tip blunt to acute

2. Perigynium body widest at or below middle; vegetative stems not leaning or branching or rooting at nodes ..... C. feta

2' Perigynium body widest above middle; vegetative stems occasionally leaning or branching or rooting at nodes ..... C. longii

Group 11B: Ligules long, sleeve-like

1. Inflorescence generally short, generally ± ovate, dense, ± head-like ..... C. pachycarpa

1' Inflorescence elliptic to oblong, dense or not, not head-like

2. Perigynium wings generally 0.1–0.25 mm wide at mid-body; contraligule generally 5–13 mm; inflorescence often ±white or green (pale brown); perigynium abruptly narrowed to distinct beak ..... C. fracta

2' Perigynium wings generally 0.3–0.5 mm wide at mid-body; contraligule generally 1–5 mm; inflorescence green or light- to rusty-brown; perigynium abruptly or gradually narrowed to beak

3. Perigynium adaxial veins generally 1–6, 0 exceeding fruit; perigynium ovate to narrow-ovate, 3.7–5.5 mm, walls translucent to opaque ..... C. multicostata

3' Perigynium adaxial veins generally 6–10, >= 3 exceeding fruit; perigynium generally lanceolate, 4.9–6.6 mm, walls generally translucent ..... C. specifica

Group 11C: Perigynium marginal wings entire (generally 0 in Carex illota)

1. Perigynium spreading, margins sharp-edged but not winged at mid-body; pistillate flower bracts and spikelets dark brown to ± black; inflorescence dense, length <= 2 × width, often wider than long; perigynium gradually narrowed to indistinct beak (beak base occasionally winged ± 0.1 mm); perigynium base with spongy or pithy interior around fruit ..... C. illota

1' Perigynium ascending, margins winged <= 0.2 mm at mid-body; pistillate flower bracts and spikelets pale to dark brown; inflorescence often ± open, length 3+ × width; perigynium abruptly or gradually narrowed to ± distinct beak; perigynium base without spongy or pithy interior around fruit

2. Perigynium wings often inrolled, beak generally with inconspicuous flap; fruit generally 1.7–2.3 mm, generally 1.1–1.5 mm wide; < 850 m ..... C. gracilior

2' Perigynium wings flat, beak with obvious white-margined flap; fruit 1.1–1.4 mm, 0.7–1 mm wide; 1000–3400 m ..... C. integra

Group 11D: Perigynium covered by pistillate flower bracts; perigynium abaxially strongly 3–14-veined

1. Inflorescence ± bent, flexible, or nodding

2. Perigynium wing generally 0.1–0.2 mm wide, inrolled, not visible in abaxial view; perigynium generally without adaxial veins, margins often entire above widest point ..... C. gracilior (2)

2' Perigynium wing generally 0.2–0.6 mm wide, flat, visible in abaxial view; perigynium often with strong adaxial veins, margins serrate above widest point

3. Perigynium beak tip brown, cylindric and entire > 0.4 mm, or flat and entire < 0.4 mm; perigynium generally ± flat except over fruit, body generally wide-elliptic ..... C. leporina (2)

3' Perigynium beak tip white, generally cylindric, entire > 0.4 mm; perigynium generally ± planoconvex, body generally narrow-elliptic ..... C. praticola

1' Inflorescence straight, stiff, erect

4. Longer perigynium 6–8.1 mm

5. Inflorescence open; perigynium beak with obvious white abaxial flap; perigynium walls thick, opaque ..... C. petasata

5' Inflorescence dense; perigynium beak with inconspicuous abaxial flap; perigynium walls thin, ± translucent ..... C. specifica

4' Longer perigynium < 6 mm

6. Perigynium 0.8–1.2 mm wide, beak indistinct, wings generally incurved ..... C. leporinella

6' Perigynium 1.3–2.6 mm wide, beak distinct or not, wings not incurved

7. Perigynium generally widest near or above middle; inflorescence generally dense, spikelets overlapped; leaf sheath mouth white; subalpine to alpine, 2500–4000 m

8. Strong adaxial perigynium veins generally 0(4); perigynium walls thin, ± translucent ..... C. phaeocephala

8' Strong adaxial perigynium veins 3–8; perigynium walls thick, opaque ..... C. tahoensis

7' Perigynium generally widest below middle; inflorescence dense or open, spikelets overlapped or not; leaf sheath mouth occasionally brown-tinged; coastal, montane, 0–3500 m

9. Perigynium adaxial veins generally reaching beak base; perigynium walls sometimes thin, ± translucent

10. Perigynium not shiny at 10×, beak tip ± flat, serrate; inflorescence elongate, generally open, green or gold; montane, 800–3500 m ..... Group 11B, couplet 2

10' Perigynium ± shiny at 10×, beak tip cylindric, entire; inflorescence ovoid, dense, generally brown or coppery; coastal, insular, or montane, < 900 m ..... C. harfordii

9' Perigynium adaxial veins 0 or generally reaching at most to fruit tip; perigynium walls generally ± thick, opaque

11. Well-developed perigynium with wing at mid-body generally 0.4–0.6 mm wide ..... C. leporina (2)

11' Well-developed perigynium with wing at mid-body <= 0.4 mm wide

12. Inflorescence generally open, lower spikelets distinct; perigynium wings generally 0.1–0.2 mm wide at mid-body, generally inrolled, not visible abaxially, margins at 16× entire from base to above widest point; perigynium upper body entire or not, beak minute-serrate; leaf blades 1.2–3 mm wide ..... C. gracilior (2)

12' Inflorescence ± dense (except on late season stems), lower spikelets often clustered or overlapped, indistinct; perigynium wings generally 0.2–0.3(0.4) mm wide at mid-body, flat, visible abaxially, margins at 16× entire from base to ± widest point; perigynium upper body, most of beak minute-serrate; leaf blades 1.3–4.6 mm wide ..... C. subbracteata

Group 11E: Larger perigynium 6–9.3 mm

1. Inflorescence ± ovate (elliptic, triangular), dense, head-like

2. Pistillate flower bracts generally dark brown to ± black; perigynium flat except over fruit ..... C. haydeniana

2' Pistillate flower bracts light brown or red-brown; perigynium planoconvex ..... C. pachycarpa

1' Inflorescence elliptic to oblong, dense or not, not head-like

3. Inflorescence bent or flexed at lower node, curved ..... C. praticola

3' Inflorescence straight

4. Perigynium base abruptly narrowed to stalk 0.5–1 mm (measured below fruit base); inflorescence generally dense, elliptic, spikelets (4)6–14; perigynium margin crinkled or flat; pistillate flower bracts green to light brown or red-brown ..... C. specifica

4' Perigynium base abruptly narrowed to stalk 1–2 mm (measured below fruit base); inflorescence open, oblong, spikelets 1–7; perigynium margin flat; pistillate flower bracts red-brown

5. Translucent pistillate flower bract margins <= 0.4 mm; perigynium beak abaxial flap inconspicuous ..... C. davyi

5' Translucent pistillate flower bract margins generally > 0.4 mm wide; perigynium beak abaxial flap obvious ..... C. petasata

Group 11F: Inflorescence bract generally 2–3 × inflorescence

1. Inflorescence ± lateral, lowest bract wide, leaf-like, erect, appearing to be continuation of stem; most perigynium beaks flat, winged, minute-serrate (cylindric, unwinged, entire portion < 0.4 mm) ..... C. unilateralis

1' Inflorescence ± terminal, lowest bract often narrower, less leaf-like, ascending or spreading, not appearing to be continuation of stem; perigynium beaks ± flat or cylindric (unwinged, entire portion > 0.4 mm)

2. Perigynium adaxial veins exceeding fruit top

3. Contraligule generally 5–13 mm; inflorescence 2.5–8 cm, generally ± white or green (to pale brown) ..... C. fracta

3' Contraligule 0 or < 3 mm; inflorescence 1.5–4 cm, generally dark brown or ± black ..... C. harfordii

2' Perigynium adaxial veins 0 or not exceeding fruit top

4. Perigynium base abruptly narrowed to distinct stalk (on dried material often bent or crumpled); perigynium strongly flattened except over fruit, or occasionally biconvex ..... C. athrostachya

4' Perigynium stalk indistinct or 0; perigynium planoconvex

5. Perigynium generally 3.5–4.7(5.7) mm; inflorescence coarse, parts large at arm's length; < 900 m ..... C. subbracteata

5' Perigynium generally 2.3–3.5 mm; inflorescence fine, parts small at arm's length; (75)700–3800 m ..... C. subfusca

Group 11G: Perigynium beak wide-winged, minute-serrate; tip cylindric, entire < 0.4 mm

1. Inflorescence bent or flexed at lowest node ..... C. scoparia var. scoparia (2)

1' Inflorescence erect, not bent or flexed at lowest node

2. Widest perigynium 2.2–3.4 mm wide

3. Perigynium wide-ovate or -elliptic or ± round, winged margin generally 0.5–1 mm wide ..... C. straminiformis

3' Perigynium lanceolate to ovate, winged margin generally 0.3–0.5 mm wide

4. Inflorescence dense, ± spheric, 10–22 mm; perigynium 4.9–5.9(6) mm ..... C. pachycarpa (2)

4' Inflorescence open, linear-oblong, 20–60 mm; perigynium (5.7)6–8.1 mm ..... C. petasata (2)

2' Widest perigynium <= 2.1 mm wide

5. Wider perigynium wings generally 0.1–0.3 mm at midbody

6. Inflorescence 2.5–8 cm; contraligule generally 5–13 mm; perigynium adaxial veins exceeding fruit generally >=3 ..... C. fracta

6' Inflorescence 1.1–3 cm; contraligule generally < 3 mm; perigynium adaxial veins generally 0 or not exceeding fruit ..... C. subfusca

5' Wider perigynium wings generally 0.3–0.5 mm at midbody

7. Inflorescence ± ovate (elliptic, triangular), ± head-like

8. Perigynium thick, planoconvex, abaxial veins 8–17, wide, tissue often sunken between veins; adaxial veins 0–12; individual spikelets generally indistinct at arm's length ..... C. pachycarpa (2)

8' Perigynium thin, flat, abaxial veins 0–8, thin, tissue not sunken between veins; adaxial veins 0–5; individual spikelets distinct at arm's length ..... C. scoparia var. scoparia (2)

7' Inflorescence oblong, lanceolate, or elliptic, generally not head-like

9. Inflorescence generally open, linear-oblong, spikelets distinct at arm's length ..... C. petasata (2)

9' Inflorescence often dense, elliptic to lanceolate or oblanceolate, at least upper spikelets indistinct at arm's length

10. Perigynium adaxial veins exceeding fruit; perigynium generally 4.9–6.6 mm, generally lanceolate ..... C. specifica

10' Perigynium adaxial veins generally shorter, not exceeding fruit or 0; perigynium 3.3–5.5 mm, generally ovate

11. Perigynium generally gradually narrowed to indistinct beak, adaxial veins obvious, (1)3–13; perigynium walls translucent to opaque ..... C. multicostata

11' Perigynium abruptly narrowed to distinct beak, adaxial veins 0 (3, inconspicuous); perigynium walls opaque ..... C. preslii

Group 11H: Perigynium beak tip generally cylindric, generally entire >= 0.4 mm

1. Perigynium flat, thin except over fruit (± inflated, convex both faces)

2. Perigynium wide-elliptic to ± round, margins occasionally crinkled or ruffled, beak distinct, 20–25% of total perigynium length; anthers early-deciduous to persistent; pistillate flower bracts 1/2 perigynium width

3. Perigynium beak <= 1.2 mm; leaves generally 0.5–2.7 mm wide when flat, in life generally folded or channeled toward base; inflorescence dense to more open, ovate, elliptic, or oblong ..... C. proposita

3' Perigynium beak generally 1.2–1.5 mm; leaves (1.7)3–4 mm wide when flat, in life flat or folded; inflorescence generally dense, ovate ..... C. straminiformis

2' Perigynium ovate to lanceolate, margins generally flat, beak indistinct or > 25% of total perigynium length; anthers generally deciduous; pistillate flower bracts > 1/2 perigynium width

4. Most perigynium distinctly short-stalked, dried stalks often bent or crumpled; inflorescence bract on some heads long-awned, wide at base ..... C. athrostachya

4' Most or all perigynium not distinctly stalked; inflorescence bract rarely long-awned or wide at base

5. Perigynium 4–6.5 mm, (2.3)2.6–4.2 mm beak tip to fruit; perigynium green, dark brown, or coppery, margins often darker than wings; stem 9–20(40) cm; subalpine to alpine ..... C. haydeniana

5' Perigynium (2.8)3.4–4.5(5.2) mm, 1.5–2.5(2.8) mm beak tip to fruit; perigynium green to light brown, center often brown, margin color generally same as wings; stem 20–110 cm; montane to alpine ..... C. microptera

1' Perigynium generally planoconvex, thick

6. Perigynium adaxial veins generally 3–10, generally exceeding fruit

7. Inflorescence elongated, oblong to elliptic, not head-like, lower spikelets generally distinct, bases generally tapered; montane

8. Perigynium 2.5–4.8(5.3) mm ..... C. mariposana

8' Perigynium (5.7)6–8.5 mm ..... C. petasata

7' Inflorescence compact, often ovoid, head-like, lower spikelets indistinct, bases generally blunt; coastal or montane

9. Perigynium margins entire from base to ± widest point, minute-serrate on beak and upper body; stems erect, not branched at nodes; sheath face tops generally pale; generally without leaf-like inflorescence bract; 1200–3450 m ..... C. abrupta

9' Perigynium margins entire from base often to above widest point, minute-serrate on beak and occasionally uppermost body; stems often leaning, occasionally branched at nodes, branches leafy or fertile; sheath face tops often brown-tinged; inflorescence bract occasionally leaf-like; < 900 m ..... C. harfordii

6' Perigynium adaxial veins 0 or short, 0 (1) exceeding fruit

10. Perigynium margins at 16× entire from base to above widest point; marginal wings at mid-body often inrolled so not visible from abaxial side ..... C. gracilior

10' Perigynium margins at 16× entire from base to ± widest point; marginal wings at mid-body generally not inrolled, visible from abaxial side

11. Pistillate flower bracts generally 4.2–5.8 mm, ± hiding perigynium

12. Inflorescence generally open, often bent or flexed at lowest node, most spikelets distinct at arm's length ..... C. praticola

12' Inflorescence generally dense, erect, most spikelets indistinct at arm's length ..... C. subbracteata (2)

11' Pistillate flower bracts generally < 4.2 mm, not hiding perigynium

13. Perigynium generally 2.3–3.5 mm, wing margin at midbody generally 0.1–0.25 mm wide; inflorescence at arm's length fine-textured, parts small ..... C. subfusca

13' Perigynium generally >= 3.5 mm, wing margin at midbody generally 0.3–0.4 mm wide; inflorescence at arm's length coarse-textured, parts large

14. Perigynium spreading; spikelet ± star-shaped, outline jagged at arm's length; pistillate flower bract dark throughout, or white margins narrow, < 0.1 mm wide ..... C. pachystachya

14' Perigynium ± ascending; spikelet not star-shaped, outline ± smooth at arm's length; pistillate flower bract generally with white margins 0.2–0.5 mm wide

15. Perigynium beaks of 2 kinds in an inflorescence, some ± flat, with smooth entire part < 0.4 mm, some cylindric, with smooth entire part > 0.4 mm; generally dry soil; 1800–3400 m, Klamath Ranges, North Coast Ranges, High Cascade Range, High Sierra Nevada, San Jacinto Mountains ..... C. preslii

15' Perigynium beaks of 1 kind, generally cylindric, smooth entire part > 0.4 mm; seasonally wet soil; < 900 m, North Coast, Outer North Coast Ranges, Central Western California, South Coast, n Channel Islands, Western Transverse Ranges ..... C. subbracteata (2)

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