Jepson Flora Project: Jepson Interchange    
 

The Jepson Manual: Higher Plants of California

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Names are linked to treatments from the Manual


Key to CAREX Key to Groups

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Spikelet 1 per inflorescence; staminate flowers above pistillate if both in a spikelet; bristle-like axis sometimes in perigynium
Group 1
  1' Spikelets > 1 per inflorescence (sometimes in a dense, head–like cluster; staminate flowers often below pistillate if both in a spikelet; bristle-like axis in perigynium 0
 
    2. Dioecious
 
      3. Spikelets > 3, ovate to round; perigynium faces glabrous; stigmas 2
2 Group 7
      3' Spikelets 2(3), narrowly oblong; perigynium faces minutely hairy at least near beak; stigmas 3(4)
 
        4. Pistillate flower bract obtuse or with a small point, ciliate or not, surface often hairy, width > or = perigynium, white margin wide; perigynium 3-sided, purplish
C. scirpoidea var. pseudoscirpoidea
        4' Pistillate flower bract acute to awned, ciliate at least at tip, surface glabrous, width < perigynium, white margin 0 or narrow; perigynium ± flat, brown to blackish
C. gigas
    2' Monoecious
 
      5. Perigynium faces hairy, at least near tip; stigmas 3–4; fruit 3–4-sided
 
        6. Mouth of leaf sheath finely toothed; inflorescence < 4 cm; lateral, pistillate spikelets 1–2, < 1.5 cm
Group 2
        6' Mouth of leaf sheath entire; inflorescence > 4 cm; lateral, pistillate spikelets generally > 2, > 1.5 cm
Group 3
      5' Perigynium faces glabrous; stigmas 2–3; fruit 2–3-sided
 
        7. Stigmas 3; fruit 3-sided
 
          8. Style tough, persistent, not jointed to fruit; perigynium veins many, each generally rib-like; staminate spikelets 1–5
Group 4
          8' Style delicate, deciduous, breaking easily at joint to fruit; perigynium veins 0–many, generally 2 rib-like; staminate spikelet 0–1
 
            9. Perigynia 2–3 per spikelet, bristle-like axis present in perigynium; pistillate flower bracts leaf–like, 1–15 cm
C. tompkinsii
            9' Perigynia > 3 per spikelet, bristle-like axis in perigynium 0; pistillate flower bracts not leaf–like, < 1 cm
Group 5
        7' Stigmas 2; fruit 2-sided
 
          10. Spikelets generally > 1.5 cm, sessile or not, ± cylindric, lower pistillate (or tip staminate), upper generally staminate
Group 6
          10' Spikelets generally < 1.5 cm, sessile, ovoid to elliptic, each generally both staminate and pistillate
 
            11. Perigynia 1–3 per spikelet, 2.2–3 mm; inflorescence 3–4 mm wide; terminal spikelet often with a conspicuous, narrow, staminate tip
C. disperma
            11' Perigynia > 3 per spikelet, 2–8 mm; inflorescence > 5 mm wide; terminal spikelet tip, if staminate, not conspicuous and narrow
 
              12. Spikelets staminate at tip, pistillate at base; perigynium thick, ribs 0 or 2
2 Group 7
              12' Spikelets staminate at base, pistillate at tip; perigynium thin to thick, ribs 2
 
                13. Perigynium often not ribbed to base, ± thin-edged above but unwinged, entire except for sometimes on beak, body strongly planoconvex, lower wall often filled with pithy tissue; stem solid
Group 8
                13' Perigynium ribbed to base, with distinct, generally serrate wings at least on upper body and beak, body planoconvex or flat, lower wall without pithy tissue; stem hollow
Group 9

Key to CAREX Group 1

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Lowest pistillate flower bracts leaf-like, 1–15 cm, base clasping perigynium; plant cespitose; bristle-like axis in perigynium present
 
    2. Upper stem round or bluntly 3-angled; longest leaves << stem, blade 1–1.5 mm wide; perigynia 1–6 per spikelet, 5–7.2 mm
C. multicaulis
    2' Upper stem sharply 3-angled; longest leaves > or ± = stem, blade 1.5–3 mm wide; perigynia generally 2–3 per spikelet, 4.5–6 mm
C. tompkinsii
  1' Lowest pistillate flower bracts not leaf-like, < 1 cm, except awns, if present, base clasping perigynium or not; plant cespitose or rhizomed; bristle-like axis in perigynium present or 0
 
    3. Spikelets unisexual, ± linear, pistillate dark, staminate pale; spikelet bract often present; perigynium faces generally hairy, at least near beak
 
      4. Pistillate flower bract obtuse or with a small point, ciliate or not, surface often hairy, width > or = perigynium, white margin wide; perigynium 3-sided, purplish
C. scirpoidea var. pseudoscirpoidea
      4' Pistillate flower bract acute to awned, ciliate at least at tip, surface glabrous, width < perigynium, white margin 0 or narrow; perigynium ± flat, brown to blackish
C. gigas
    3' Spikelets bisexual, oblong to triangular, pale or dark; spikelet bract 0 (except sometimes C. nigricans); perigynium faces glabrous or hairy
 
      5. Leaf blade flat to folded, not rolled, not quill-like, < or > 1 mm wide
 
        6. Perigynium 4.9–7 mm, 1.7–2.5 mm wide, bristle-like axis within present; moist to dry places
C. geyeri
        6' Perigynium 2.5–4.6 mm, 0.8–1.5 mm wide, bristle-like axis within 0; wet places
 
          7. Pistillate flower bracts early deciduous; spikelet 6–10 mm wide; lowest perigynia spreading to reflexed, beaks conspicuous in inflorescence, faces unveined; 2300–3700 m
C. nigricans
          7' Pistillate flower bracts persistent; spikelet 2–3 mm wide; perigynia ascending, beaks 0, faces veined; 0–700 m
C. leptalea
      5' Leaf blade rolled, quill-like, < or ± = 1 mm wide
 
        8. Stigmas 2; fruit 2-sided; bristle-like axis in perigynium present; wet places
C. capitata
        8' Stigmas 3; fruit 3-sided; bristle-like axis in perigynium present or 0; moist to dry places
 
          9. Perigynium flat, thin, > fruit, 2.5–7 mm, 0.9–4.8 mm wide, faces glabrous; style base not black, not persistent, style not exserted
 
            10. Perigynium 2.5–4.1 mm, 0.9–2 mm wide, fruit width > distance from fruit to perigynium side; spikelet elliptic to narrowly conic, 3–6 mm wide
C. subnigricans
            10' Perigynium 4–7 mm, 2.1–4.8 mm wide, fruit width < distance from fruit to perigynium side; spikelet widely conic, 6–10 mm wide
C. breweri var. breweri
          9' Perigynium 3-sided to round, thick, ± = fruit, 1.9–3.7 mm, 1.3–2.1 mm wide, faces generally hairy at least just below beak; style base black, persistent, style exserted
C. filifolia
            11. Perigynium 1.9–3 mm, body tip tapered, beak 0–0.3 mm; fruit 1.6–2.2 mm; longest pistillate flower bracts (except awns) generally < 2.5 mm, generally < perigynia
var. erostrata
            11' Perigynium 2.9–3.7 mm, body tip generally abruptly narrowed, beak 0.1–0.8 mm; fruit 2.2–3 mm; longest pistillate flower bracts (except awns) generally > 3 mm, generally = or > perigynia
var. filifolia

Key to CAREX Group 2

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Spikelet bract purple; stigmas generally 4; fruit 4-sided; leaf sheath mouth V-shaped, blade sickle-shaped; pistillate flower bract ciliate; solitary pistillate spikelets 0
C. concinnoides
  1' Spikelet bract green; stigmas 3; fruit 3-sided; leaf sheath mouth U-shaped, blade generally not sickle-shaped (except C. brevicaulis); pistillate flower bract not ciliate; solitary pistillate spikelets present or 0
 
    2. Staminate spikelet of taller inflorescences 5–10 mm; faces of most perigynia unveined or with a few short veins
 
      3. Stem scabrous at least on 1 angle except near base; leaf blade generally stiff, folded, generally ± sickle-shaped, bright green; plants in ± continuous stands; perigynium 3.8–4.5 mm, 1.3–2.3 mm wide, beak tip notched in front < 0.1 mm; coastal
2 C. brevicaulis
      3' Stem glabrous or scabrous on angles only just below inflorescence, sometimes scabrous nearly to base; leaf blade stiff or not, generally not sickle-shaped, ± flat, bright or gray-green; plants cespitose; perigynium 2.4–5 mm, 1–1.7 mm wide, beak tip notched in front > 0.1 mm (if < 0.1 mm, not near coast); coastal or inland
C. rossii
    2' Staminate spikelet of taller inflorescences 10–30 mm (except sometimes C. brainerdii); faces of most perigynia veined or several-ribbed at least below (except C. brevicaulis, sometimes C. inops)
 
      4. Solitary pistillate spikelets generally 0, sometimes on long stalks; perigynia generally > 5 per spikelet; staminate spikelet 12–30 mm; pistillate flower bract tip generally acuminate or with a minute point; High Cascade Range (Mount Shasta area)
C. inops subsp. inops
      4' Solitary pistillate spikelets present, on long or short stalks; perigynia generally < 6 per spikelet; staminate spikelet generally 10–17 mm; pistillate flower bract tip obtuse to awned; most of California Floristic Province
 
        5. Perigynium face veins 0 or few, short; leaf blade generally sickle-shaped; stem generally < 15 cm — plants in ± continuous stands
2 C. brevicaulis
        5' Perigynium faces generally veined or several-ribbed at least below; leaf blade generally not sickle-shaped; stem generally > 10 cm
 
          6. Perigynium beak tip to fruit top 1–2 mm; basal leaf sheaths dark purple-red; fruit generally tan or brown; fresh leaves gray-green; lowest spikelet bract sheath of bisexual inflorescence > or = 2 mm; bisexual inflorescence generally < longer leaves
C. brainerdii
          6' Perigynium beak tip to fruit top 0.4–1.3(1.6) mm; basal leaf sheaths brown to red; fruit generally white; fresh leaves ± bright green; lowest spikelet bract sheath of bisexual inflorescence generally < 2 mm; bisexual inflorescence < or > longer leaves
C. globosa

Key to CAREX Group 3

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Style tough, persistent, not jointed to fruit, bent; lowest spikelet bract > inflorescence, sheathless
 
    2. Leaf blade hairy; perigynium many-ribbed, body ovate, 5–8 mm, beak teeth 0.7–1.5 mm, outcurved; lateral spikelets with < 100 ascending perigynia
C. sheldonii
    2' Leaf blade glabrous; perigynium 2-ribbed, with few or 0 veins on faces, body obovate, 3–5 mm, beak teeth < 0.5 mm, straight; lateral spikelets with 150–300 spreading perigynia (see Group 4)
C. spissa
  1' Style fragile, deciduous, jointed to fruit, not bent (base sometimes bent, persistent); lowest spikelet bract < to > inflorescence, sheathed or not
 
    3. Lowest spikelet bract sheath < 5 mm
 
      4. Perigynium thin-walled, beak tip unnotched or notched only on back generally < 0.2 mm
 
        5. Leaf blade glabrous except sometimes near sheath; spikelets dark; pistillate flower bract < perigynium; talus, 2600–3900 m
C. congdonii
        5' Leaf blade conspicuously hairy; spikelets greenish; pistillate flower bract often > perigynium; moist to wet places, 1200–2600 m
C. sartwelliana
      4' Perigynium conspicuously thick-walled, beak tip notched on back and front > 0.2 mm
 
        6. Leaf blade strongly V-folded at least near base, basal blades not minute; pistillate flower bract not ciliate, acute, < or ± = perigynium; lowest spikelet stalk generally included in bract; perigynium green to gold, ribs strong, sometimes obscured by hair; dry forest edges, often in pumice
2 C. halliana
        6' Leaf blades flat or rolled, basal minute; pistillate flower bract ciliate, awned, > perigynium; lowest spikelet generally sessile; perigynium generally purplish, ribs weak; wet places
 
          7. Upper leaf ligules > 2 mm, thin, membranous; leaf blade flat, not rigid, < or > inflorescence, 1.5–5 mm wide, slender tip short, sheath mouth densely hairy or not but not ciliate; lowest inflorescence internode 0.5–0.9 mm wide; perigynium beak teeth ± outcurved; style base generally straight; lower leaf sheath fronts often not shredding; generally marshy places, in standing water or not
C. lanuginosa
          7' Upper leaf ligules < 2 mm, thick, tough; leaf blade rolled, rigid, >> inflorescence, 0.5–2 mm wide, slender tip long, sheath mouth often ciliate; lowest inflorescence internode generally < 0.8 mm wide; perigynium beak teeth generally ± erect; style base generally bent; lower leaf sheath fronts shredding; lake, pond shores, generally in standing water
C. lasiocarpa
    3' Lowest spikelet bract sheath > 5 mm
 
      8. Leaf blade hairy; pistillate flower bract surface hairy, margin not ciliate
 
        9. Perigynium 3.8–5.5 mm, base long-tapered, < upper 1/3 of body hairy, beak 0.5–1 mm; terminal spikelet staminate at least at tip
C. gynodynama
        9' Perigynium 3.5–4 mm, base short-tapered, at least upper 1/2 of body hairy, beak > 1 mm; terminal spikelet generally pistillate at least at tip
C. hirtissima
      8' Leaf blade glabrous or very sparsely hairy; pistillate flower bract surface glabrous or midrib sometimes hairy, margin ciliate or not
 
        10. Perigynium beak < 0.5 mm; leaf sheath front often red or red-dotted (see Group 5)
 
          11. Perigynium hairs appressed, inconspicuous; fruit 1.7–2.5 mm; pistillate flower bract ciliate
C. mendocinensis
          11' Perigynium hairs spreading, conspicuous; fruit 3.2–3.5 mm; pistillate flower bract not ciliate
C. triquetra
        10' Perigynium beak > 0.6 mm; leaf sheath front not red or red-dotted
 
          12. Perigynium 5–8 mm; fruit 2.7–3.3 mm
C. obispoensis
          12' Perigynium < 5.5 mm; fruit < 2.5 mm
 
            13. Lowest spikelet bract > inflorescence; leaves stiff, ascending, at least lower part of blades sharply V-folded; spikelets stiffly erect, lowest spikelet stalk not or short-exserted; perigynium strongly many-ribbed
2 C. halliana
            13' Lowest spikelet bract << inflorescence; leaves not stiff, spreading, blades not sharply V-folded; spikelets erect to nodding, lowest spikelet stalk short- to long-exserted; perigynium 2-ribbed, less often strongly veined as well
 
              14. Spikelet bract sheath mouth generally deeply Y- or V-shaped, often purple-banded at top, sheath ± expanded to mouth or not; perigynium ascending, generally primarily red-brown or purple, beak tip to fruit top > 2 mm; pistillate flower bract tip acute or minutely pointed; lateral spikelets generally purplish to brown, tips tapered (see Group 5)
C. fissuricola
              14' Spikelet bract sheath mouth generally shallowly U-shaped or truncate, generally not purple-banded at top, sheath linear; perigynium widely ascending to spreading, generally primarily green, beak tip to fruit top < 2.5 mm; pistillate flower bract tip obtuse to acute; lateral spikelets generally 2-colored (perigynia vs. flower bracts), tips truncate or tapered (see Group 5)
C. luzulina var. luzulina

Key to CAREX Group 4

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Lower spikelets staminate at tip; plant 1–2 m; perigynium beak 0.1–0.8 mm, often bent; style bent (keys also in Group 3)
C. spissa
  1' Lower spikelets pistillate; plant < 1.5 m; perigynium beak > 1 mm, straight; style straight or bent
 
    2. Leaf sheath, blade lower surface soft-hairy; perigynium ascending, beak teeth 1.1–3 mm, outcurved
C. atherodes
    2' Leaf sheath, blade lower surface glabrous; perigynium ascending to reflexed, beak teeth 0.1–2.3 mm, outcurved or not
 
      3. Lower spikelets on long, nodding stalks; pistillate flower bract generally white or cream with pale reddish center, awn > body; fruit 1.2–2 mm
 
        4. Perigynium stalked, beak notch 1.1–2.3 mm, outcurved, body ± angled; pistillate flower bract awn linear; ligule length < or = width
C. comosa
        4' Perigynium ± sessile, beak notch 0.2–1 mm, erect, body ± not angled; pistillate flower bract awn lanceolate; ligule length >> width
C. hystricina
      3' Lower spikelets ± erect, stalks 0 or short; pistillate flower bract generally mostly green to purplish, awn 0 or < body; fruit generally 1.1–2.3 mm
 
        5. Perigynia in many dense rows, ascending-spreading to reflexed, 3.9–7 mm, abruptly narrowed above, beak 1–2 mm, teeth 0.1–0.8 mm; rhizomes long; stem angles blunt; ligule length < or ± = width
C. utriculata
        5' Perigynia in a few ± open rows, ascending, 4–11 mm, tapered or ± abruptly narrowed above, beak 1–3 mm, teeth 0.2–1.5 mm; rhizomes short; stem angles sharp; ligule length > width
C. vesicaria
          6. Perigynium generally 7–11 mm, tapered above, beak 2–3 mm, teeth 0.2–1.5 mm; lower leaf sheath fronts generally shredding to network or fringe of veins
var. major
          6' Perigynium generally 4–8 mm, + abruptly narrowed above, beak 1–2 mm, teeth 0.2–1 mm; loewr leaf sheath sheath fronts generally not shredding
var. vesicaria

Key to CAREX Group 5

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Leaf blade with long, soft hairs, sheath front brownish; fruit ± = perigynium body; dry places
C. whitneyi
  1' Leaf blade without long, soft hairs, sheath front white to red; fruit < or ± = perigynium body; wet or dry places
 
    2. Lowest spikelet bract sheath > 6 mm; lower leaf sheath fronts often shredding
 
      3. Stem ± 2–8 cm, < leaves; perigynia 3–8 per spikelet, 1.3–2 mm, 0.4–0.9 mm wide, spines few, curved, on upper body margins; pistillate spikelet < 5 mm, flower bracts early deciduous; leaf blade margins and midrib at 10× coarsely serrate
C. tiogana
      3' Stem > 10 cm, generally > leaves; perigynia > 5 per spikelet, > 2 mm, > 0.8 mm wide, spines 0; pistillate spikelet > 1 cm, flower bracts not early deciduous; leaf blade margins and midrib at 10 × at most finely serrate
 
        4. Perigynium body tip wide conic, beak generally < 0.2 mm or indistinct, tip unnotched; fruit > 2 mm
 
          5. Leaf blade 6–14 mm wide, flat, not glaucous; perigynium 4.3–6.5 mm, not glaucous, with 1 fruit; fruit 2.7–3.3 mm; plant cespitose
C. hendersonii
          5' Leaf blade 1–3.5 mm wide, flat or V folded, ± glaucous; perigynium 3.5–4.6 mm, green glaucous, with 1–2 fruits; fruit 2–3.5 mm; plant rhizomed
C. livida
        4' Perigynium body tip conic to rounded, beak > 0.2 mm, tip notched in front; fruit generally < 2.5 mm
 
          6. Lower spikelet bract blades ascending-spreading, >> inflorescence; perigynia spreading to reflexed, crowded; upper spikelets densely clustered
2 C. viridula var. viridula
          6' Lower spikelet bract blades erect to ascending, < or ± = inflorescence; perigynia appressed to spreading, crowded or not; upper spikelets sometimes densely clustered
 
            7. Perigynium, pistillate flower bract midstripe, leaf blade lower side glandular papillate; plant strongly rhizomed; leaf blade gray green
C. californica
            7' Perigynium, pistillate flower bract midstripe, leaf blade lower side not glandular, papillate or not; plant rhizomed or cespitose; leaf blade gray or bright green
 
              8. Lowest spikelet bract blade < inflorescence, sheath mouth hairy; perigynium beak < 0.5 mm; leaf sheath front often red or red dotted — lateral spikelets linear, 15–50 mm (keys also in Group 3)
C. mendocinensis
              8' Lowest spikelet bract blade << inflorescence, sheath mouth glabrous; perigynium beak > 0.5 mm; leaf sheath front white
 
                9. Perigynia dark purple, 1.7–2.5 mm wide, flat margin > 1/2 fruit width, beak, pistillate flower bract (except sometimes awn) glabrous; spikelet bract sheath conspicuously expanded to mouth, mouth > 2 mm wide, generally shallowly U-shaped, with wide purple band at top; lowest spikelet stalk long exserted from bract sheath, nodding; leaf blade 5–20 mm wide — lateral spikelets > 1.2 cm, purple to dark brown
C. luzulifolia
                9' Perigynia green to purple, < 1.7 mm wide (if wider and with flat margin around fruit then beak, pistillate flower bract tip and midrib ciliate); spikelet bract sheath linear or slightly expanded to mouth, mouth < 2 mm wide, U-, V-, or Y-shaped, sometimes with narrow but without wide purple band at top; lowest spikelet stalk exserted or not from bract sheath, erect or nodding; leaf blade generally 3–10 (1.5–15) mm wide
 
                  10. Perigynium 2.5–4.5 mm, generally mostly green, partly purple, beak tip generally ciliate, generally < 1.4 mm to fruit top; lowest spikelet stalk included in or exserted generally < 1 cm from bract sheath; leaf blade 1.5–6 mm wide — lowest spikelet bract bladed
 
                    11. Inflorescence > 15 cm, lowest internode 10–25 cm; pistillate flower bract generally white with green midrib; leaf blade 3–6 mm wide; terminal spikelet generally pistillate below tip; longest lateral spikelets > 15 mm; larger perigynia 3.5–4.5 mm
C. albida
                    11' Inflorescence generally < 15 cm, lowest internode generally < 10 cm; pistillate flower bract generally at least partly red brown, sometimes all white; leaf blade generally 1.5–3(4) mm wide; terminal spikelet generally staminate; longest lateral spikelets < 15 mm; larger perigynia 2.7–3.5(4) mm
C. lemmonii
                  10' Perigynium 3–5.5 mm, green to purple, beak tip ciliate or not, > 1.5 mm to fruit top; lowest spikelet stalk generally exserted > 1 cm from bract sheath; leaf blade (1.5)3–10 mm wide
 
                    12. Spikelet bract sheath ± expanded to mouth or not, mouth generally deeply Y- or V-shaped, often with purple band at top; perigynium ascending, generally ± red brown or purple, beak tip to fruit top > 2 mm; pistillate flower bract tip acute or minutely pointed (keys also in Group 3)
C. fissuricola
                    12' Spikelet bract sheath linear, mouth generally shallowly U-shaped or truncate, generally without purple band at top; perigynium ascending to spreading, ± green or purple, beak tip to fruit top < 2.5 mm; pistillate flower bract tip obtuse to acute
C. luzulina
                      13. Perigynium generally mostly purple, ± stalked, ascending, 3–4.5 mm, body ± = fruit body; lateral spikelet tip tapered, sides ± deeply jagged; pistillate flower bract dark purple, midstripe generally < 0.2 mm wide, generally not to tip, tip acute; leaf blade 1.5–6 mm wide
var. ablata
                      13' Perigynium generally ± green to red-brown, sessile, ascending spreading to spreading, 3.5–5.5 mm, body ± > fruit body; lateral spikelet tip truncate, rounded, or abruptly narrowed to staminate part, sides ± smooth or bristly, not deeply jagged; pistillate flower bract generally red-brown, midstripe > 0.2 mm wide, ± to tip, tip obtuse to acute; leaf blade 4–10 mm wide (keys also in Group 3)
var. luzulina
    2' Lowest spikelet bract sheath < 5 mm; lower leaf sheath fronts sometimes shredding
 
      14. Perigynium body tapered to widely conic tip, generally beakless, papillate above; style base often persistent, black, exserted; lowest spikelet on nodding stalk; root conspicuously hairy; plant long-rhizomed; pistillate flower bract generally brown
C. limosa
      14' Perigynium body tapered or abruptly rounded to short, linear beak, papillate above or not; style base generally not persistent, brown, included or not; lowest spikelet sessile or on erect or nodding stalk; root not conspicuously hairy; plant cespitose or rhizomed; pistillate flower bract ± brown or dark purple to black with pale midstripe
 
        15. Pistillate flower bract < perigynium, awn hairy; perigynium beak teeth hairy
C. serratodens
        15' Pistillate flower bract < or > perigynium, awn 0 or glabrous; perigynium beak teeth glabrous or 0
 
          16. Terminal spikelet staminate at tip or throughout
 
            17. Perigynia > 60 per spikelet, spreading; leaf blade 8–20 mm wide, with small, raised, irregularly spaced cross walls; stem sharply 3-winged; lateral spikelets 3.5–14 cm
C. amplifolia
            17' Perigynia < 50 per spikelet, ascending or spreading; leaf blade < 10 mm wide, without small raised cross walls; stem sharply or obtusely 3-angled, ± unwinged; lateral spikelets < 4 cm
 
              18. Perigynium appressed to ascending, generally ± purple at least above, body flat or flat around fruit, ± unveined, width >> fruit; pistillate flower bract with pale midstripe generally to tip, awned or tip long-tapered; lowest spikelet often on nodding stalk
 
                19. Spikelets generally conspicuously 2-colored (perigynia vs. flower bracts), erect; perigynium not papillate, body elliptic to obovate, 3-sided with flat margin around fruit; basal leaf blades not minute
2 C. heteroneura var. heteroneura
                19' Spikelets purple, often nodding; perigynium papillate, body ovate, ± flat or 3-sided; basal leaf blades generally minute
C. spectabilis
              18' Perigynium spreading, generally green, body spheric or flat around fruit above, veined or many ribbed, width ± = fruit; pistillate flower bract with pale midstripe 0 or not to tip, awn 0; lowest spikelet sessile or on erect stalk
 
                20. Staminate spikelet oblong, > 2 mm wide; lower spikelet bract blades ascending, < or > inflorescence, not bright yellow-green; perigynium 1.6–2.1 mm wide, flat around fruit above
C. raynoldsii
                20' Staminate spikelet linear, 1–2 mm wide; lower spikelet bract blades ascending spreading, >> inflorescence, bright yellow-green; perigynium 0.9–1.5 mm wide, not flat around fruit
2 C. viridula var. viridula
          16' Terminal spikelet pistillate above, generally staminate at base
 
            21. Lowest spikelet generally on long, nodding stalk; spikelets 6–10, generally > 2 cm; lowest spikelet bract > inflorescence; perigynium 3.9–5.5 mm, very flat, > 3 × fruit width
C. mertensii
            21' Lowest spikelet sessile or on short, erect stalk; spikelets 1–6, < or > 2 cm; lowest spikelet bract < inflorescence; perigynium < 4.5 mm, ± round to flat, < 3 × fruit width (often > 3 × in C. heteroneura var. epapillosa)
 
              22. Perigynium 1.6–3 mm, obovate, edge generally with a few stiff hairs on and just below beak, upper body generally papillate; terminal spikelet generally pistillate, or staminate at base or tip; pistillate flower bract white-margined
C. parryana var. hallii
              22' Perigynium > 2.5 mm (except sometimes C. norvegica), ovate to obovate, edge ± without hairs, upper body papillate or not; terminal spikelet pistillate above, generally staminate at base; pistillate flower bract white-margined or not
 
                23. Upper body of perigynium conspicuously papillate
 
                  24. Pistillate flower bract awned, white margin or tip indistinct or 0; lower leaf sheath fronts shredding — plant rhizomed
C. buxbaumii
                  24' Pistillate flower bract obtuse to with a small point, with distinct white margin and tip; lower leaf sheath fronts not shredding
 
                    25. Perigynium ± inconspicuous in generally head-like inflorescence, ± = pistillate flower bract, 1.3–2 mm wide, body at least 1/4 empty above fruit, ± flat; leaves gray-green; plant cespitose, 10–30 cm; ± dry, rocky places, 3000–3900 m, often on summits
C. albonigra
                    25' Perigynium conspicuous in generally ± open inflorescence, >> pistillate flower bract, 1–1.3 mm wide, body ± filled by fruit, 3-sided; leaves green; plant short-rhizomed, 10–70 cm; wet places, 2900 m
C. norvegica
                23' Upper body of perigynium not or inconspicuously papillate
 
                  26. Pistillate flower bract generally < 1 mm wide, red-brown to purple, length >, width <<, color ± = perigynium; inflorescence generally head-like; stem generally < 30 cm; 2400–4100 m
C. helleri
                  26' Pistillate flower bract generally > 1.2 mm wide, dark purple, length < or >, width < or >, color generally not = perigynium; inflorescence not head-like, at least lowest spikelet not clustered with others; stem 25–100 cm; 1800–3800 m
C. heteroneura
                    27. Perigynium > 3.5 mm, flat margin (0.3(0.5–0.7 mm wide fruit base to perigynium base 0.5–1.1 mm
var. epapillosa
                    27' Perigynium generally < 3.5 mm, flat margin < 0.4 mm wide;fruit base to perigynium base 0–0.4 mm
var. heteroneura

Key to CAREX Group 6

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Lowest spikelet bract sheath > 4.5 mm; lower spikelet stalks often from near plant base; longest pistillate spikelets < 2.5 cm; perigynium green or white to orange, papillate, ± fleshy
 
    2. Perigynium 2.5–4 mm, body tapered to red-brown-margined tip, not translucent; lower pistillate flower bracts stout-awned, often leaf-like; lower staminate flower bracts generally ± long-awned, like spikelet bract; spikelets often > 1 per lower branch
C. saliniformis
    2' Perigynium 1.8–3.1 mm, body widely blunt-tipped or slightly tapered, tip not red-brown except on beak (if present), ± translucent; lower pistillate flower bracts obtuse to narrow-awned, not leaf-like; lower staminate flower bracts not long-awned, not like spikelet bract; spikelets 1 per node throughout inflorescence
 
      3. Pistillate flower bracts generally crowded, red-brown to purplish, often > perigynia, tip generally widely obtuse; spikelet bract sheath mouth V-shaped; spikelets, except basal, generally densely clustered, terminal 1 generally pistillate at least at tip
C. garberi
      3' Pistillate flower bracts generally not crowded, white to red-brown, < perigynia, tip obtuse to awned; spikelet bract sheath mouth U-shaped; spikelets not densely clustered, terminal one sometimes pistillate at tip
 
        4. Lower pistillate flower bracts not appressed against, often falling before fully expanded perigynia; staminate portion of terminal spike 0.9–2 mm wide, lower flower bracts 2–3.5(4) mm; perigynium spheric in spike, generally sessile, body generally strongly ribbed, tip generally not conspicuously papillate at 10 ×, body when fresh orange, when dry orange or gold to purplish, often white above, ± squashed below
C. aurea
        4' Lower pistillate flower bracts closely appressed against, falling after fully expanded perigynia; staminate portion of terminal spike (1.8)2–3.5 mm wide, lower flower bracts 3–6 mm; perigynium ± obovate, stalked, body veined, generally not ribbed, tip conspicuously papillate at 10 ×, body gold or white when fresh, when dry greenish white or pale gold, lower part sometimes gold, generally not squashed
C. hassei
  1' Lowest spikelet bract sheath < 4 mm; lower spikelet stalks not from near plant base; longest pistillate spikelets often > 3 cm; perigynium green, brown, or purple, papillate or not, not fleshy
 
    5. Perigynium wall ± tough, resisting puncture, brown, sometimes red- or purple-dotted
 
      6. Perigynium wall very thick, very tough, beak 0–0.3 mm, notch at tip 0–0.1 mm, tip glabrous; fruit 1.4– 2.5 mm, often deeply indented on 1 or both sides
 
        7. Lowest spikelet ± truncate at base, stiff, straight, axis (1.8)2–8 cm, stalk long, nodding; perigynium dull, papillate, ± conspicuously veined; fruit wide-stalked; lower leaf sheath fronts not shredding; long-rhizomed
C. lyngbyei
        7' Lowest spikelet tapered at base, flexible, nodding, axis (2.5)3–15 cm, stalk 0 or ± short, generally erect; perigynium shiny, not papillate, inconspicuously veined; fruit sessile; lower leaf sheath fronts shredding; rhizomed, forming beds or large, dense, raised clumps
C. obnupta
      6' Perigynium wall thick, ± tough, beak 0.2–0.6 mm, notch at tip > 0.1 mm, tip hairy; fruit 1.3–2 mm, not indented
 
        8. Pistillate flower bract awned, tip or awn hairy; lower leaf sheath fronts shredding, blades generally not tufted at stem base, not blue-glaucous; fully mature spikelets uniformly brown, not pressing flat; perigynium spreading, 3–4.5 mm
C. barbarae
        8' Pistillate flower bract obtuse to awned, tip or awn glabrous; lower leaf sheath fronts not shredding, blades generally tufted at stem base, generally blue-glaucous; mature spikelets generally 2-colored, pressing ± flat; perigynium ascending, 2.6–4 mm
2 C. nebrascensis
    5' Perigynium wall thin, soft, easy to puncture, green to brown, often red or purple-dotted or -blotched
 
      9. Perigynium beak 0.2–0.6 mm, tip notched > 0.1 mm, teeth minutely hairy; fresh leaf blade generally blue-glaucous; leaves generally densely tufted at stem base
2 C. nebrascensis
      9' Perigynium beak generally < 0.4 mm, tip notched < 0.1 mm, glabrous; fresh leaf blade generally not blue-glaucous; leaves tufted at stem base or not
 
        10. Veins on perigynium faces 0 or indistinct; lower leaf sheath fronts generally not shredding
 
          11. Spikelets 4.5–11.5 cm, tips generally staminate, lower stalks generally nodding, < 11 cm; lowest spikelet bract generally > inflorescence; leaf sheath front purple-dotted, mouth purple-brown
C. aquatilis var. dives
          11' Spikelets < 10 cm, tips generally pistillate, lower stalks 0 or generally erect, < 4.2 cm; lowest spikelet bract generally < or ± = inflorescence; leaf sheath front red- or purple-dotted or not, mouth not or weakly purple
 
            12. Lowest spikelet 10–100 mm, its bract generally ± = inflorescence, its stalk 0–42 mm; inflorescence generally open, lowest internode 20–180 mm; perigynium ± red-dotted or -blotched, weakly papillate; fruit shiny
C. aquatilis var. aquatilis
            12' Lowest spikelet 8–30 mm, its bract generally < 1/2 inflorescence, its stalk 0–15 mm; inflorescence ± dense, lowest internode 5–45 mm; perigynium generally purple above, strongly papillate; fruit dull
C. scopulorum var. bracteosa
        10' Veins on perigynium back face or on both faces generally distinct; lower leaf sheath fronts shredding or not
 
          13. Perigynium stalk generally > 0.1 mm, body ± slightly, abruptly narrowed near base, green or white over fruit, purple-dotted or not, papillate; lower leaf sheaths backs not scabrous, front not shredding (except sometimes longitudinally); pistillate flower bract widely obtuse or acute, unawned, <, often << perigynium; leaf blades 1–3.5 mm wide, basal not minute; lowest spikelet bract > or = inflorescence
C. lenticularis
            14. Lower spikelets >> internodes between, lowest 4–6 mm wide; perigynium > pistillate flower bract, stalk 0.4–0.7 mm
var. limnophila
            14' Lower spikelets < or less often > internodes between, lowest 3–4 mm wide; perigynium often >> pistillate flower bract, stalk < 0.5 mm
 
              15. Perigynium veins generally 3 on back, 0 or < 3 on front, body often purple-dotted, beak dark throughout or with purple or brown ± triangle from tip, stalk < 0.2 mm
var. impressa
              15' Perigynium veins generally 5–7 on back and front, body green, beak purple or brown only at tip, stalk 0.2–0.5 mm
var. lipocarpa
          13' Perigynium ± sessile, body not even slightly abruptly narrowed near base, green to brown, often purple-dotted or -blotched, papillate or not; lower leaf sheath backs scabrous, fronts shredding; pistillate flower bract obtuse to awned, < or > perigynium; leaf blades 2–12 mm wide, basal minute or not; lowest spikelet bract < or > inflorescence
 
            16. Plant 1–1.5 m; leaf blade 4–12 mm wide; bladeless sheath > 7 mm wide at midlength, keeled; perigynium (2.7)3–4.5 mm; staminate spikelets 2–7, terminal often > 5 cm; lateral spikelets generally 5–20 cm, 5–7 mm wide, stalks 0 or long, ± nodding; lowest spikelet bract leaf-like, generally > inflorescence
C. schottii
            16' Plant generally < 1 m; leaf blade 2–9 mm wide; bladeless sheath < 7 mm wide at midlength, not keeled; perigynium 2–4 mm; staminate spikelets generally 1–2, terminal < 5 cm; lateral spikelets (1.5)2–9 cm, < 6 mm wide, stalks 0 or erect; lowest spikelet bract leaf- or bristle-like, < or > inflorescence
 
              17. Plant forming dense stands but not large, raised clumps, long-rhizomed; lowest spikelet generally < 5 mm wide, its bract > or ± = inflorescence; pistillate flower bract often > perigynium body, acute or tapered to generally pointed tip, often < 0.5 mm wide; perigynium 2.2–3.1 mm, ± weakly 1–3-veined both sides, green, purple-dotted above or not, weakly papillate; leaf blade 2–7 mm wide
C. angustata
              17' Plant forming large, dense, raised clumps connected by rhizomes or not; lowest spikelet generally > or ± = 5 mm wide, its bract < or > inflorescence; pistillate flower bract generally < perigynium body, obtuse- to acuminate-tipped, generally > 0.5 mm wide; perigynium 2.2–4 mm, 3–9-veined on back, green or above purple, papillate or not; leaf blade 2–5 mm wide
 
                18. Perigynium 1.2–1.6(1.8) mm wide, generally dark purple on beak, upper body; leaf blades 2–4 mm wide, lower sheath backs generally without raised cross-walls; rocky or sandy streambeds below high-water mark; clumps not connected by rhizomes, not in ± continuous stands
C. nudata
                18' Perigynium 1.4–2.2 mm wide, sometimes dark purple on beak, upper body; leaf blades 3–5 mm wide, lower sheath backs with small, raised, irregularly spaced cross-walls; streambanks, marshy areas, meadows; clumps connected by rhizomes, in ± continuous stands or not
C. senta

Key to CAREX Group 7

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Plant staminate
 
    2. Plant cespitose; spikelets > 1 per lower node or branch; leaf sheath front generally red-dotted
 
      3. Anther > 1.9 mm; leaf sheath front not cross-wrinkled, mouth generally with membranous, tongue-like extension, not copper, not purplish, without thick rim
2 C. alma
      3' Anther < 1.8 mm; leaf sheath front often cross-wrinkled, mouth generally U-shaped, copper or purplish, often with thick rim
2 C. cusickii
    2' Plant rhizomed; spikelets generally 1 per node throughout inflorescence; leaf sheath front generally not red-dotted
 
      4. Anther with narrow, < 0.1 mm tip; leaf blade < 1.5 mm wide; rhizome < 2 mm thick; inflorescence < 20 mm
2 C. eleocharis
      4' Anther with 0.1–1 mm awn; leaf blade 1–5 mm wide; rhizome 1–5 mm thick; inflorescence < 40 mm (except some C. praegracilis)
 
        5. Rhizome 1–2 mm thick, brown; anther awn 0.2–1 mm, glabrous; leaf sheath mouth with thick rim; inflorescence (7)10–25 mm wide
2 C. douglasii
        5' Rhizome 2–5 mm thick, dark brown; anther awn 0.1–0.4 mm, glabrous or hairy; leaf sheath mouth fragile or with thick rim; inflorescence < 15 mm wide except in some C. pansa
 
          6. Longest anther awns 0.2–0.4 mm, filaments generally included; plant generally < 30 cm, on coast or islands — sand
3 C. pansa
          6' Longest anther awns 0.1–0.2 mm, filaments exserted; plant 20–75 cm, near coast or inland
 
            7. Anther awn generally hairy at 20 ×, slender, tip tapered or obtuse; leaf sheath mouth often with thick rim, without brown stripe; leaf blade 1.5–3 mm wide
3 C. praegracilis
            7' Anther awn glabrous at 20 ×, stout, tip obtuse; leaf sheath mouth without thick rim, often with brown stripe across; leaf blade 2–5 mm wide
3 C. simulata
  1' Plant bisexual or pistillate
 
    8. Perigynium wall filled with pithy tissue below, base often ± whitish; spikelet bracts often conspicuous
 
      9. Perigynium long-tapered to poorly defined beak, beak tip to fruit top > 1/2 total length, body widest ± at base
 
        10. Perigynium pale to dark brown, veins on back few, on front 0; pistillate flower bract white or widely white-margined; fresh stem not spongy
2 C. alma
        10' Perigynium green to medium brown, veins many both sides, each a rib; pistillate flower bract pale to black, white-margined or not; fresh stem spongy (except C. jonesii)
 
          11. Leaf sheath front with thick rim at mouth, not cross-wrinkled, back white-spotted; perigynium 3–4.5 mm; fresh stem deeply concave between sharp angles or wings, spongy
C. nervina
          11' Leaf sheath front without thick rim at mouth, often cross-wrinkled below mouth, back generally not white-spotted; perigynium 2.5–6 mm; fresh stem deeply or shallowly concave between blunt or sharp angles or wings, spongy or firm
 
            12. Spikelets > 1 per lower node or branch; inflorescence 2–10 cm, 1–3 cm wide, spikelets >> 10; leaf blade 5–11 mm wide; perigynium 3.6–6 mm, 1.5–1.8 mm wide
C. stipata var. stipata
            12' Spikelet 1 per node throughout inflorescence; inflorescence 1–2.5 cm, 0.6–1.5 cm wide, spikelets < 10; leaf blade 1–5 mm wide; perigynium 2.5–4 mm, 0.8–1.5 mm wide
 
              13. Margin of perigynium beak and upper body entire; leaves generally tufted near stem base, sheath fronts generally ± not cross-wrinkled, mouth without tongue-like extension; pistillate flower bract gold to black; fresh stem ± concave between ± sharp angles, ± firm; plant generally not forming large raised clump
2 C. jonesii
              13' Margin of perigynium beak and generally upper body serrate at least on 1 side; leaves generally not tufted near stem base, sheath fronts often cross-wrinkled, mouth with tongue-like extension; pistillate flower bract brown, white-margined; fresh stem deeply concave between sharp angles or wings, spongy; plant often forming large raised clump
C. neurophora
      9' Perigynium short-tapered or abruptly narrowed to conic or ± linear beak, beak tip to fruit top < 1/2 total length, body widest at or above base
 
        14. Perigynium back (near base) with lengthwise groove 0.1–0.3 mm wide, beak with white flap on back
 
          15. Plant with rhizomes; perigynium beak 0.2–0.6 mm, generally < 1/4 body
3 C. simulata
          15' Plant cespitose (rhizomes 0); perigynium beak 0.7–1.5 mm, generally > 1/3 body
 
            16. Leaf sheath front near mouth copper or purplish, often cross-wrinkled, blade 2.5–6 mm wide; inflorescence 4–8 cm, ± flexible, lower internodes >> others; perigynium 2–4 mm, 1–2 mm wide, lengthwise groove 0.1–0.3 mm wide near base
2 C. cusickii
            16' Leaf sheath front near mouth white or at most with a narrow brown margin, not cross-wrinkled, blade 1–3 mm wide; inflorescence 2–5 cm, stiff, lower internodes sometimes > but generally not >> than others; perigynium 2–3 mm, 0.9–1.4 mm wide, lengthwise groove 0.2–0.3 mm wide
C. diandra
        14' Perigynium back (near base) with lengthwise groove 0 or < 0.1 mm wide, beak without flap on back
 
          17. Spikelets > 1 per lower node or branch; inflorescence 2–15 cm, (0.8)1–3 cm wide, spikelets > (often >>) 10; plant cespitose
 
            18. Perigynium generally < 3 mm, 0.4–0.7 mm thick, length generally < or ± 2 × width, body deltate, front wall filled with pithy tissue in whitish U-shaped area around fruit, ± flat over fruit, veins 0 or few, short, beak often entire; lower pistillate flower bract awns generally > 1 mm
C. vulpinoidea
            18' Perigynium generally > 3 mm (except often C. dudleyi), 0.7–1.1 mm thick, length generally > 2 × width, body ovate to deltate, front wall filled with pithy tissue below, rounded over fruit, veined or not, beak serrate or ciliate; lower pistillate flower bract awns < or > 1 mm
 
              19. Pistillate flower bract primarily white or widely white-margined, ± = or > perigynium
 
                20. Perigynium 3.5–4.3 mm, gold to dark brown, body ovate, widest ± at base; inflorescence 2.5–15 cm; lower leaf sheath front red-dotted, generally not cross-wrinkled, back not white-spotted
2 C. alma
                20' Perigynium 2–3.7(4) mm, gold, body diamond-shaped, widest ± at middle; inflorescence 1.5–5(6.5) cm; lower leaf sheath front sometimes red-dotted, generally cross-wrinkled, back often white-spotted
3 C. dudleyi
              19' Pistillate flower bract pale gold to brown, narrowly or not white-margined (base white or not), < perigynium — these 2 species intergrade
 
                21. Perigynium generally 3–4.5 mm (if < 3 mm, length < 2 × width), body ovate, with fruit below top, tapered to beak, with indistinct or wide flat margin around fruit, beak conic, generally > 0.6 mm wide 0.2 mm above fruit
2 C. densa
                21' Perigynium generally 2–3.7 mm, length > 2 × width, body ± diamond-shaped, with fruit at top, generally abruptly narrowed above, with narrow flat margin around fruit, beak conic to ± linear, generally < 0.6 mm wide 0.2 mm above fruit
3 C. dudleyi
          17' Spikelet 1 per node throughout inflorescence (if > 1 per lower node or branch, plant rhizomed); inflorescence 0.8–5 cm, generally < 1 cm wide (–2.5 in C. douglasii, C. pansa), spikelets generally < 10; plant cespitose or rhizomed
 
            22. Pistillate flower bract white to greenish; perigynium green to pale gold; leaf sheath front not cross-wrinkled; plant cespitose; alien
 
              23. Perigynium 1.2–2.3 mm wide, beak 0.4–0.8 mm, serrate; fruit 1.1–1.7 mm wide; leaf blade 1–3 mm wide
C. leavenworthii
              23' Perigynium 0.8–1.2 mm wide, beak 0.5–1 mm, entire; fruit 0.8–1 mm wide; leaf blade 0.7–1.5 mm wide
C. retroflexa var. texensis
            22' Pistillate flower bract gold to black, white-margined or not; perigynium gold to brown; leaf sheath front cross-wrinkled or not; plant cespitose or rhizomed; native
 
              24. Plant cespitose; perigynium beaks entire, conspicuous in inflorescence, body shiny, entire above
2 C. jonesii
              24' Plant rhizomed; perigynium beaks serrate, generally ± inconspicuous in inflorescence, body shiny or dull, serrate above
 
                25. Perigynium < 2.6 mm, shiny, beak generally < 1/4 body, style exserted; lower pistillate flower bracts ± awned
3 C. simulata
                25' Perigynium > 2.6 mm, shiny or dull, beak > 1/4 body, style exserted or not; lower pistillate flower bracts minutely pointed to awned
 
                  26. Perigynium generally shiny, base narrowed for > 0.3 mm below fruit; pistillate flower bract generally shiny, generally dark brown, less often pale; longest anther awns 0.2–0.4 mm, filaments generally included; plant 10–30 cm; fruit 1.4–2.1 mm; inflorescence generally ovate; on coast or islands, sand
3 C. pansa
                  26' Perigynium ± dull, base narrowed for < 0.3 mm below fruit; pistillate flower bract ± dull, gold to medium brown; longest anther awns 0.1–0.2 mm, filaments exserted; plant generally > 20 cm; fruit 1.2–1.9 mm; inflorescence oblong-elliptic; near coast or inland, ± moist, often alkaline places, including sand
3 C. praegracilis
    8' Perigynium wall not filled with pithy tissue, brown to blackish; spikelet bracts conspicuous or not
 
      27. Spikelets > 1 per lower node or branch; inflorescence 2–8 cm, 1–3 cm wide, spikelets >, often >> 10; lower leaf sheath fronts often cross-wrinkled; plant cespitose
 
        28. Perigynium generally 3–4.5 mm (if < 3 mm, length < 2 × width), body ovate, with fruit below top, ± tapered above, with indistinct or wide flat margin around fruit, beak wide-conic, > 0.6 mm wide 0.2 mm above fruit
2 C. densa
        28' Perigynium generally 2–3.7 mm, length > 2 × width, body diamond-shaped, with fruit at top, generally abruptly narrowed to beak, with narrow flat margin around fruit, beak narrow-conic to linear, < 0.6 mm wide 0.2 mm above fruit
3 C. dudleyi
      27' Spikelet 1 per node throughout inflorescence (if > 1 per lower node or branch, plant rhizomed); inflorescence 0.5–5 cm, 0.4–1.6 (–2.7 in C. douglasii, C. pansa) cm wide, spikelets generally < 10; lower leaf sheath fronts not cross-wrinkled; plant cespitose or rhizomed
 
        29. Perigynium beak, upper body entire, body ± shiny
 
          30. Plant < 6 cm; rhizome long, generally wavy; leaf > inflorescence, blade 0.7–1.5 mm wide; perigynium 2.8–3.5 mm, > pistillate flower bract; fruit round to square; open, dry, gravelly or rocky slopes, 3700–4000 m
C. incurviformis var. danaensis
          30' Plant 5–30 cm; rhizome short, straight; leaf < inflorescence, blade 2–4 mm wide; perigynium 3.3–4.8 mm, < pistillate flower bract; fruit ovate; open, often rocky places wet from snow-melt, 1800–4000 m — some immature plants of C. nervina, C. neurophora will key here
C. vernacula
        29' Perigynium beak, upper body serrate, body shiny or dull
 
          31. Perigynium conspicuously spreading, > pistillate flower bract (except C. occidentalis)
 
            32. Perigynium back bulged so that marginal ribs are on front, not sides, very shiny, beak < 1 mm; inflorescence 4–8 mm wide; fruit 1.6–2.5 mm
C. vallicola
            32' Perigynium back not bulged (marginal ribs are on sides), dull or ± shiny, beak < or > 1 mm; inflorescence 5–15 mm wide; fruit 1.2–2.1 mm
 
              33. Inflorescence ± open, 1.5–3 cm; perigynium ± = pistillate flower bract
2 C. occidentalis
              33' Inflorescence dense (sometimes lowest spikelet separate), 0.7–2 cm; perigynium > pistillate flower bract
 
                34. Perigynium 2–3.5 mm, pale green to brown; fruit ± sessile; pistillate flower bract awned, white or greenish, midrib green; lower spikelet bracts > spikelets; alien, lawns
C. cephalophora
                34' Perigynium 3.4–5 mm, brown with green margin; fruit long-stalked; pistillate flower bract acute to long-acuminate, red-brown, midrib green, margin white; lower spikelet bracts generally < spikelets; native, rocky-gravelly slopes, meadow edges
C. hoodii
          31' Perigynium appressed to ascending, < or = pistillate flower bract
 
            35. Plant cespitose or short-rhizomed, bisexual; perigynium 1.5–2 mm wide, base narrowed for > 0.4 mm below fruit
 
              36. Perigynium ascending, beak 0.6–1.2 mm; fruit 1.3–2 mm; lowest spikelet bract like pistillate flower bract, < inflorescence
2 C. occidentalis
              36' Perigynium appressed, beak 1.2–3 mm; fruit 1.8–2.3 mm; lowest spikelet bract bristle-like, often > inflorescence
C. tumulicola
            35' Plant long-rhizomed, often unisexual; perigynium 1.3–2 mm wide, base narrowed for < or > 0.4 mm below fruit
 
              37. Rhizome < 2.1 mm thick; leaf blade margin generally inrolled, (sometimes ± flat)
 
                38. Stigmas 4–6 mm, persistent, style 1.8–3.5 mm, exserted; perigynium 3.5–4.6 mm, gold to medium brown, beak 0.9–1.8 mm, ± = body; leaf blade 1–2.5 mm wide; inflorescence on pistillate plant 1.5–3.5 cm, 1.3–2.7 cm wide; leaf sheath mouth with thick rim; generally dioecious
2 C. douglasii
                38' Stigmas < 4 mm, deciduous, style < 1.5 mm, included; perigynium 2.5–3.5 mm, white to black, beak 0.4–1(1.2) mm, < body; leaf blade 0.5–1.5 mm wide; inflorescence on pistillate or bisexual plant < 2 cm, < 1 cm wide; leaf sheath mouth without thick rim; monoecious or dioecious
2 C. eleocharis
              37' Rhizome > 2 mm thick; leaf blade flat or V-shaped
 
                39. Perigynium generally shiny, base narrowed for > 0.3 mm below fruit; pistillate flower bract generally shiny, generally dark brown, less often pale; longest anther awns 0.2–0.4 mm, filaments generally included; plant 10–30 cm; fruit body 1.4–2.1 mm; inflorescence generally ovate; on coast or islands, in sand
3 C. pansa
                39' Perigynium ± dull, base narrowed for < 0.3 mm below fruit; pistillate flower bract ± dull, gold to medium brown; longest anther awns 0.1–0.2 mm, filaments exserted; plant generally > 20 cm; fruit 1.2–1.9 mm; inflorescence oblong-elliptic; near coast or inland, ± moist, often alkaline places, including sand
3 C. praegracilis

Key to CAREX Group 8

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Inflorescence < 15 mm, dark brown, lowest inflorescence internode < 1 mm; perigynia spreading, entire, beaks conspicuous in inflorescence
C. illota
  1' Inflorescence > 15 mm, green to medium brown, lowest inflorescence internode > 2 mm; perigynia appressed to spreading, entire or serrate, beaks conspicuous in inflorescence or not
 
    2. Perigynium wall filled at least in lower 1/2 of body with pithy tissue, upper body ± papillate
 
      3. Perigynium 2–3.4 mm, beak 0.6–1.2 mm, > 1/4 body, conic; lower leaf sheath fronts at least sparsely minutely red-dotted; inflorescence dense, spikelets 7–15
2 C. arcta
      3' Perigynium 1.5–3 mm, beak < 0.55 mm, < 1/4 body, wide-conic; leaf sheath fronts not red-dotted; inflorescence dense or open, spikelets < 10
 
        4. Perigynium beak without brown stripe or flap; pistillate flower bract white, sometimes gold or pale brown; inflorescence 2–15 cm, ± open, lowest spikelet generally < 2 × lowest internode; leaf blade 1.5–4 mm wide; plant 10–80 cm; 1100–3200 m
C. canescens
        4' Perigynium beak with brown stripe or flap along middle of back; pistillate flower bract light brown, margin and tip white; inflorescence (1)1.5–2.5 cm, often dense, lowest spikelet generally > 2 × lowest internode; leaf blade 1.2–2.5 mm wide; plant 10–30 cm; 2400–3500 m
C. praeceptorum
    2' Perigynium wall not or filled only near base with pithy tissue, body not papillate
 
      5. Perigynia spreading to reflexed, widest ± at base, wall filled with pithy tissue there; spikelets ± star-shaped; staminate flower bracts of terminal spikelet appressed, internodes between them 2/3–3/4 their length; terminal spikelet base narrowly tapered
 
        6. Perigynium 1.9–3.3 mm, beak densely serrate, 1/4–1/3 body, tip to fruit top 0.5–1 mm; stem edges sharp; wet places, often calcareous, not sphagnum bogs
C. interior
        6' Perigynium (2.4)2.6–4.8 mm, beak sparsely serrate, > or ± = body, tip to fruit top 0.8–2 mm; stem edges ± blunt; acidic, generally in sphagnum bogs
C. echinata
          7. Perigynium (2.4)2.6–4 mm, ± abruptly narrowed above, front generally unveined, with bulge of pithy tissue below fruit, beak tip to fruit top generally 1–1.5 mm; fruit ± round, 1.1–1.6 mm, 0.8–1.3 mm wide; leaf blades 1–3.3 mm at widest
subsp. echinata
          7' Perigynium 3.5–4.8 mm, tapered above, front 2–12-veined, without bulge of pithy tissue, beak tip to fruit top 1.4–2.2 mm; fruit ovate, 1.5–2.2 mm, 1–1.5 mm wide; leaf blades 1.7–4 mm at widest
subsp. phyllomanica
      5' Perigynia appressed to spreading, widest near or above base, wall filled with pithy tissue there or not; spikelets not star-shaped; staminate flower bracts of terminal spikelet appressed to spreading, internodes between them < or > 1/2 their length; terminal spikelet base round to narrowly tapered
 
        8. Perigynium beak conic, 0.5–1.3 mm; perigynium ascending, 2–4 mm, ovate; lower pistillate flower bracts obtuse to acute
 
          9. Inflorescence ± dense; leaf blade 2–4 mm wide; perigynium beak conic, minutely serrate at 10×, not recurved
2 C. arcta
          9' Inflorescence open; leaf blade 1–2 mm wide; perigynium beak narrow-conic, often entire at 10×, sometimes recurved
C. laeviculmis
        8' Perigynium beak long-tapered, (1)1.2–2.7 mm; perigynium appressed to spreading, 2.8–5 mm, lanceolate to narrowly elliptic; lower pistillate flower bracts awned
 
          10. Spikelets linear to oblong, generally > 13 mm, generally not jagged-sided, base of lower ones staminate, narrowly tapered; perigynium 3.3–5 mm, beak teeth > 0.2 mm, often outcurved; pistillate flower bract generally golden-brown at least near center, generally covering fruit, awn often > 1.2 mm
C. bolanderi
          10' Spikelets round to oblong, 5–13 mm, jagged-sided, base of lower ones generally ± pistillate, generally rounded or short-tapered; perigynium 2.8–4.5 mm, beak teeth generally < 0.3 mm, erect to incurved; pistillate flower bract generally white, generally not covering fruit top, awn < 1.2 mm
C. deweyana subsp. leptopoda

Key to CAREX Group 9

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Larger perigynia 5.7–8.1 mm, lanceolate, appressed to ascending, planoconvex, width generally < 1/2 length, beak tip cylindric, ± entire; fruit > 2.1 mm; inflorescence open; spikelet base long-tapered
 
    2. Perigynium front veins 0–few, < 1/2 fruit length, body ± abruptly narrowed to beak, generally cream-white, generally translucent
2 C. praticola
    2' Perigynium front veins > 1/2 fruit length, body tapered to beak, cream-white to brown, generally not translucent
 
      3. Spikelets 1–3; pistillate flower bract reddish, not or narrowly white-margined, covering ± 3/4 perigynium; perigynium front veins 0–3 long, 1–3 short, beak tip red-brown; staminate flower bract not or narrowly white-margined; inflorescence orange-brown, 2nd lowest internode 2–6.5 mm when present
C. davyi
      3' Spikelets 3–8; pistillate flower bract generally white or widely white-margined, ± covering perigynium; perigynium front veins 5–8, long, beak tip red-brown, very tip white; staminate flower bract widely white-margined; inflorescence often whitish, 2nd lowest internode generally 4–11 mm
C. petasata
  1' Larger perigynia < 6 mm (if > 6 mm, then inflorescence dense, perigynium flat, beak tip flat, or fruit < 2.1 mm), lanceolate to elliptic, appressed to spreading, planoconvex or flat except over fruit, width < or > 1/2 length, beak tip cylindric-entire or flat-minutely serrate; fruit < 2 mm; inflorescence open or dense; spikelet base long-tapered or not
 
    4. Perigynium wing entire throughout, < 0.1 mm wide, beak tip cylindric
C. integra
    4' Perigynium wing minutely serrate at least on upper body and beak, < or > 0.1 mm wide, beak tip cylindric or flat
 
      5. Lower 2–3 spikelet bracts (sometimes not present or damaged late in season) elongate, ± leaf-like, at least lowest >> inflorescence; inflorescence dense, < 3 cm
 
        6. Perigynium body planoconvex, ovate to elliptic, ascending to spreading, wall ± tough; fruit 0.9–1.4 mm wide; coastal or on islands
2 C. harfordii
        6' Perigynium body flat around fruit, lanceolate to narrowly ovate, appressed to ascending, wall delicate; fruit 0.7–1.2 mm wide; coastal or inland
 
          7. Most perigynium beak tips unwinged and entire for > 0.4 mm, generally green, very tip white; larger perigynia generally < 1.5 mm wide, lanceolate or narrowly ovate, ± stalked, fruit near body base; inflorescence < 1.5 cm except on vigorous plants, axis ± erect; lowest spikelet bract ascending, generally < 1.8 mm wide
C. athrostachya
          7' Most perigynium beak tips unwinged and entire for < 0.4 mm, end generally red-brown; larger perigynia > 1.2 mm wide, ovate, generally sessile, fruit near body middle; inflorescence generally > 1.5 cm, axis generally ascending; lowest spikelet bract generally ± erect, often > 2 mm wide
C. unilateralis
      5' Lower 2–3 spikelet bracts generally like pistillate flower bracts or bristle-like, < inflorescence, lowest sometimes leaf-like and > inflorescence; inflorescence dense or open, < or > 3 cm
 
        8. Ligule > 2.5 mm; spikelets sometimes > 1 per lower node or branch; leaf sheath often with a membranous tongue-like extension above mouth — inflorescence generally (2.5)3–8 cm
 
          9. Spikelet sides smooth; perigynia ± appressed, 4–6 mm, (1.2)1.5–2.5 mm wide, flat except over fruit, beak tip to fruit top 2.8–3.8 mm, beak tip cylindric and entire for < 0.4 mm; pistillate flower bract < perigynium, gold or brown; leaf sheath front white, membranous; lower spikelet bracts generally like pistillate flower bracts; spikelets 1 per lower node or branch
C. scoparia
          9' Spikelet sides rough; perigynia appressed to ascending, 2.5–5 mm, 1–2.1 mm wide, planoconvex or ± flat, beak tip to fruit top 1.3–3 mm, beak tip cylindric and entire for < or > 0.4 mm; pistillate flower bract ± covering perigynium, generally white or pale gold, sometimes brownish; leaf sheath front green, ribbed at least in lower 1/2; lower spikelet bracts leaf- or bristle-like; spikelets often > 1 per lower node or branch
 
            10. Leaf sheath front green-ribbed except for a ± triangular, delicate, membranous, white area extending < 6 mm below mouth and generally a membranous ± tongue-like brownish extension above mouth; flat margin of perigynium body including wing 0.3–0.6 mm wide, beak tip reddish
C. feta
            10' Leaf sheath front sometimes green-ribbed above but with at least a narrow, delicate, membranous white strip extending > 10 mm below mouth and a membranous ± tongue-like white extension above mouth; flat margin of perigynium body including wing 0.1–0.4 mm wide, beak tip pale
 
              11. Larger perigynia > 4 mm, tapered above, beak tip to fruit top (1.5)2–2.5 mm, beak tip cylindric and entire for < 0.4 mm; lowest spikelet bract base generally around stem
2 C. amplectens
              11' Larger perigynia < 4(4.5) mm, ± abruptly narrowed above, beak tip to fruit top generally < 2 mm, beak tip cylindric and entire for > 0.4 mm; lowest spikelet bract base often not around stem
C. fracta
        8' Ligule generally < 2 mm; spikelets 1 per lower node or branch; leaf sheath generally without tongue-like extension above mouth
 
          12. Perigynium generally > 1.8 mm wide, body round to widely ovate, flat margin including wing > 0.4 mm wide
 
            13. Most pistillate flower bracts ± = perigynium, covering most of its beak; perigynia generally inconspicuous in inflorescence; spikelet oblong or fusiform to rounded, 3–5 mm wide
 
              14. Leaf blade 1.5–4 mm wide, flat; perigynium beak tip red-brown, with white flap along middle of back or not; fruit ± sessile
 
                15. Perigynium front veins generally several to fruit top, upper body margin gold, beak without white flap along middle of back; pistillate flower bract center gold, tip white
2 C. ovalis
                15' Perigynium front veins generally 0–2 to fruit top, upper body margin green, beak with white flap along middle of back or not; pistillate flower bract center generally green, tip brown to gold
6 C. preslii
              14' Leaf blade 0.5–2.5 mm wide, folded to rolled; perigynium beak tip brown to red-brown, white at very tip, with white flap along middle of back; fruit often stalked
 
                16. Perigynium body 1.2–2.5 mm wide, ± = pistillate flower bract width, length 2.2–4 × width
5 C. phaeocephala
                16' Perigynium body 1.8–3 mm wide, 2–3 × pistillate flower bract width, length 1.7–2.6 × width
2 C. proposita
            13' Most pistillate flower bracts < perigynium, covering part but not most of its beak; perigynia generally conspicuous in inflorescence; spikelet ovate to spheric, generally > 4 mm wide
 
              17. Perigynium planoconvex
 
                18. Perigynium veins on back > 8, on front generally > 3
2 C. multicostata
                18' Perigynium veins on back < 8, on front generally < 3
 
                  19. Spikelet ± spheric; inflorescence green; flat perigynium margin including wing 0.4–0.7 mm wide, beak tip 0.3–0.4 mm wide; pistillate flower bract white to pale green or pale gold; alien
C. molesta
                  19' Spikelet ovate; inflorescence generally 2-colored, brown and green; flat perigynium margin including wing (0.1)0.2–0.5 mm wide, beak tip 0.1–0.3 mm wide; pistillate flower bract brown to gold, generally with green center; native
6 C. preslii
              17' Perigynium flat except over fruit
 
                20. Perigynium margin crinkled at least above, beak tip cylindric and entire for < 0.4 mm, red-brown, very tip white; leaf blade flat
C. straminiformis
                20' Perigynium margin generally not crinkled, beak tip cylindric and ± entire for > 0.3 mm, green to black; leaf blade flat or folded or margin downcurved
 
                  21. Perigynium abruptly narrowed to short beak, body 2–3 × pistillate flower bract width, flat margin including wing 0.4–0.9 mm; leaf blade 0.5–2.5 mm wide, generally folded or margin downcurved; spikelets ± distinct, widely ovate to spheric; plant 10–30 cm; anthers ± persistent; 3000–4100 m
2 C. proposita
                  21' Perigynium ± tapered to long beak, body < 2 × pistillate flower bract width, flat margin including wing 0.2–0.7 mm; leaf blade 1.5–6 mm wide, flat; spikelets distinct or not, ovate; plant 5–100 cm; anthers deciduous; 1500–4200 m
 
                    22. Perigynium 4.2–6.5 mm, beak tip to fruit top generally > 2.5 mm, flat margin including wing 0.3–0.7 mm wide; fruit 1.2–2.3 mm, stalk 0.4–0.7 mm; inflorescence dark brown, less often greenish, spikelets indistinct; plant often < 20 cm; stem often decumbent; 2400–4200 m
2 C. haydeniana
                    22' Perigynium 2.9–5 mm, beak tip to fruit top generally < 2.5 mm, flat margin including wing 0.2–0.5 mm wide; fruit 1–1.6 mm, stalk 0.3–0.5 mm; inflorescence green to less often dark brown, spikelets ± indistinct; plant generally > 20 cm; stem erect; 1500–3400 m
2 C. microptera
          12' Perigynium < 2.2 mm wide, body ovate, elliptic, lanceolate, or fusiform, flat margin including wing < 0.4 mm wide
 
            23. Perigynium veins on back > 9, on front generally > 3; pistillate flower bract often white or with wide white margin; ± dry places
 
              24. Perigynium beak tip cylindric and entire for > 0.4 mm, brown to reddish, white at very tip, with minute white flap along middle of back; leaf blade 0.5–2.5 mm wide; inflorescence whitish to medium- or orange-brown
 
                25. White margin of pistillate flower bract < 0.3 mm wide; fruit 1.5–2.1 mm, 0.8–1.2 mm wide, 0.2–0.5 mm thick; perigynia ascending, body ± planoconvex, front veins often uneven or 0, < fruit top, beak tip to fruit top 1.5–2.6 mm; spikelets ascending, > 5 mm wide; inflorescence > 10 mm wide
5 C. phaeocephala
                25' White margin of pistillate flower bract 0.3–0.6 mm wide; fruit 1.8–2.3 mm, 1.1–1.4 mm wide, 0.5–0.7 mm thick; perigynia appressed, body strongly planoconvex, front veins even, generally 5–8 to fruit top, beak tip to fruit top 0.6–2 mm; spikelets appressed, < 5 mm wide; inflorescence < 11 mm wide
C. tahoensis
              24' Perigynium beak tip cylindric and entire for < 0.4 mm, pale gold to reddish; leaf blade 2–6.5 mm wide; inflorescence white-green to light brown
 
                26. Inflorescence 4–6.5 cm, white-green, lowest internode 7–20 mm, next 4.7–7 mm; pistillate flower bract white, tinged pale gold or not, ± covering perigynium; lowest spikelet bract leaf-like, base generally around stem; perigynium generally > 4 mm, beak tip to fruit top (1.5)2–2.5 mm
2 C. amplectens
                26' Inflorescence 1–4.6 cm, gold, brown, or brown and green, lowest internode < 8 mm, next 2–5 mm; pistillate flower bract gold to brown, with wide white margin or not, < perigynium; lowest spikelet bract like pistillate flower bract or ± leaf-like, base partly around stem; perigynium 3.5–6.6 mm, beak tip to fruit top 1.8– 3.4 mm
 
                  27. Perigynium 3.5–6.3 mm, generally > 1.8 mm wide, ovate to widely so, beak tip to fruit top generally < 2.5 mm, flat margin including wing 0.2–0.5 mm wide, fruit stalk 0.4–0.8 mm; leaf sheath front membranous, not or weakly ribbed, blade flat, ligule < 2 mm; inflorescence ± triangular, sometimes elongate, spikelets generally < 6
2 C. multicostata
                  27' Perigynium 4.8–6.6 mm, generally < 1.8 mm wide, lanceolate to fusiform, beak tip to fruit top generally > 2.5 mm, flat margin including wing 0.2–0.4 mm wide, fruit stalk 0.6–1 mm; leaf sheath front often ± firm, ribbed, blade flat or folded, ligule < 2.5 mm; inflorescence generally oblong, spikelets generally > 6
C. specifica
            23' Perigynium veins on back < 9, on front 0 to > 3; pistillate flower bract gold or brown, with white margin or not; wet or dry places
 
              28. Inflorescence open, lowest bract internode > 4 mm; spikelets distinct, at least the lowest < 2 × lowest internode
 
                29. Perigynium boat-shaped, < 4.2 mm, < 1.2 mm wide, wings incurved to front, < 0.12 mm wide, beak tips inconspicuous in inflorescence; most pistillate flower bracts covering perigynia; spikelet generally fusiform; leaf blade 0.5–1.5(2) mm wide
2 C. leporinella
                29' Perigynium not boat-shaped, < or > 4.2 mm, < or > 1.2 mm wide, wings not incurved to front, < or > 0.12 mm wide, or, if perigynium boat-shaped and wings incurved to front, beak tips conspicuous in inflorescence; most pistillate flower bracts < perigynia if wings incurved to front; spikelet ovate, elliptic, or fusiform; leaf blade 0.5–4.5 mm wide
 
                  30. Perigynium front veins several, even, to above fruit
 
                    31. Perigynium body ± or not planoconvex, flat margin including wing 0.2–0.6 mm wide, beak tip with or without white flap along middle of back; pistillate flower bract generally covering perigynium
 
                      32. Perigynium length 1.8–2.6 × width, beak tip red-brown; leaf blade 1.5–4 mm wide
2 C. ovalis
                      32' Perigynium length 2.2–4 × width, beak tip brown to red-brown, white at very tip, with a white flap along middle of back; leaf blade 0.5–2.5 mm wide
5 C. phaeocephala
                    31' Perigynium body planoconvex, flat margin including wing generally < 0.25 mm wide, beak tip without white flap along middle of back; pistillate flower bract generally not covering perigynium
 
                      33. Lowest 2 inflorescence internodes together < 1/3, generally ± 1/5 total inflorescence length
3 C. abrupta
                      33' Lowest 2 inflorescence internodes together < 1/2, generally ± 1/3 total inflorescence length
 
                        34. Upper spikelets distinct, base of at least lowest spikelet often long-tapered; perigynium sometimes boat-shaped with wings incurved to front, wall delicate, beak < 2/5, generally ± 1/3 perigynium length; fruit 0.8–1.3 mm wide; lowest spikelet bract > lowest spikelet or not, < inflorescence, base generally not around stem; plant self-supported; 1200–3200 m
3 C. mariposana
                        34' Upper spikelets generally indistinct, base wedge-shaped or rounded; perigynium not boat-shaped, wings not incurved to front, wall ± tough, beak < 1/2, generally ± 2/5 perigynium length; fruit 0.9–1.7 mm wide; lowest spikelet bract generally > lowest spikelet, < or > inflorescence, base often around stem; plant often supported by vegetation; < 900 m
3 C. subbracteata
                  30' Perigynium front veins 0 or few, uneven, sometimes 1–2 to above fruit
 
                    35. Longer pistillate flower bracts generally < 3.5 mm
 
                      36. Fruit 1–1.6 mm, 0.7–1.2 mm wide; perigynium appressed to spreading, generally < 3.5 mm, flat margin including wing generally < 0.2 mm wide, body whitish green, pale gold, or light brown, upper margin green or gold; spikelet fine-textured (parts small)
2 C. subfusca
                      36' Fruit generally 1.4–2.3 mm, 0.9–1.7 mm wide; perigynium ascending-spreading, generally > 3.5 mm, flat margin including wing generally > 0.2 mm wide, body green to brown; spikelet coarse-textured (parts large)
 
                        37. Spikelets generally > 5, not or only lower distinct; pistillate flower bract generally reddish to brown ± throughout; perigynium beak tip to fruit top 1.5–2.9 mm, back bulged, upper body margin widely dark brown or coppery (narrowly green to gold), ± = pistillate flower bract in color; fruit generally 1.4–1.7(1.2–2.2) mm, ovate; inflorescence 9–24 mm
3 C. pachystachya
                        37' Spikelets 3–7, distinct; pistillate flower bract brown to gold, center generally green; perigynium beak tip to fruit top (1.8)2.4–3.7 mm, front, back bulged, upper body margin widely green to gold, not = pistillate flower bract in color; fruit generally 1.7–2.1(1.5–2.3) mm, ± squared; inflorescence 17–25 mm
6 C. preslii
                    35' Longer pistillate flower bracts generally > 3.5 mm
 
                      38. Perigynium beak tip with white flap along middle of back, very tip generally white; pistillate flower bract generally covering perigynium
 
                        39. Fruit 0.2–0.5 mm thick; perigynium beak 0.5–1.2 mm, beak tip to fruit top (1.5)1.8–2.6 mm, body generally gold to brown (cream-white), sometimes translucent, flat or ± planoconvex; leaf blade 0.5–2.5 mm wide; inflorescence stiff to ± flexible, erect, 10–35 mm, 2nd lowest internode 2–4.5 mm; stem 5–40 cm; inland, 2700–3900 m
5 C. phaeocephala
                        39' Fruit 0.5–0.7 mm thick; perigynium beak 1–1.6 mm, beak tip to fruit top 2–3.7 mm, body generally cream-white, translucent, planoconvex; leaf blade 1.5–4 mm wide; inflorescence flexible, often nodding, 15–50 mm, 2nd lowest internode (2.5)4–10 mm; stem 25–80 cm; coastal or inland, < 3200 m
2 C. praticola
                      38' Perigynium beak tip without white flap on back, very tip generally not white; pistillate flower bract generally not covering perigynium
 
                        40. Perigynium wall delicate, beak tip to fruit top (1.8)2.4–3.7 mm; spikelets generally distinct; lowest spikelet bract < or > lowest spikelet, like pistillate flower bract or bristle-like; stem self-supporting; 30–3000 m, ± inland
6 C. preslii
                        40' Perigynium wall ± tough, beak tip to fruit top 1.5–2.5 mm; upper spikelets generally indistinct; lowest spikelet bract generally > lowest spikelet, bristle- or leaf-like; stem often supported by vegetation; < 900 m, coastal
 
                          41. Lowest inflorescence internode often > lowest spikelet, lowest 2 internodes together < 14 mm, < 1/2 inflorescence length; leaf blade 1.2–3 mm wide; perigynium wing often entire except on and just below beak, front with 0–4 veins ± = fruit; coastal or inland, 0–700 m
C. gracilior
                          41' Lowest inflorescence internode generally < lowest spikelet, lowest 2 internodes together < 9 (11) mm, < 2/5 inflorescence length; leaf blade 1.3–4.5 mm wide; perigynium wing serrate on upper 1/2 body, front with 0–7 veins ± = fruit; coastal, < 900 m
3 C. subbracteata
              28' Inflorescence dense, lowest bract internode < 3.5 mm; spikelets distinct or not, > 2 × lowest internode
 
                42. Perigynia < 4.2 mm, < 1.2 mm wide, boat-shaped, wings incurved to front, generally ± 0.1 mm wide, beak tips inconspicuous in inflorescence; most pistillate flower bracts covering perigynia; spikelet fusiform; leaf blade 0.5–1.5(2) mm wide
2 C. leporinella
                42' Perigynia < or > 4.2 mm, < or > 1.2 mm wide, not boat-shaped, wings not incurved to front or, if boat-shaped and wings incurved to front, beak tips conspicuous in inflorescence; most pistillate flower bracts < perigynia; spikelet ovate, elliptic, or fusiform; leaf blade 0.5–4.5 mm wide
 
                  43. Perigynium body much wider than fruit, flat except over fruit or planoconvex due to air within, beak tip to fruit top ± > 1/2 perigynium length
 
                    44. Perigynium 4.2–6.5 mm, beak tip to fruit top generally > 2.5 mm; fruit stalk 0.4–0.7 mm, body (1.2)1.4–2.3 mm; inflorescence generally dark brown, less often greenish; plant often < 20 cm, stem often decumbent; 2400–4200 m
2 C. haydeniana
                    44' Perigynium 2.9–5.4 mm, beak tip to fruit top generally < 2.5 mm; fruit stalk 0.3–0.5 mm, body 1–1.8 mm; inflorescence green to dark brown; plant generally > 20 cm, stem erect; 1400–3400 m
 
                      45. Perigynium 3.6–5.4 mm, beak generally < 1 mm, 1/4–1/3 body length, tip cylindric, unwinged for generally > 0.6 mm, entire, dark brown; fruit 1.2–1.8 mm
3 C. abrupta
                      45' Perigynium 2.9–5 mm, beak 1–1.5 mm, 1/3–1/2 body length, tip cylindric, unwinged for generally < 0.5 mm, ± serrate, green or brown; fruit body 1–1.6 mm
2 C. microptera
                  43' Perigynium body as wide as fruit, planoconvex, not flat, beak tip to fruit top < or > 1/2 perigynium length
 
                    46. Lowest 2 inflorescence internodes together < 1/3 inflorescence length
 
                      47. Fruit filling < 1/2 perigynium body; perigynium front veins (2)4–8, generally > fruit, beak > 2/5 perigynium length, perigynium sometimes boat-shaped, wings incurved to front; 1400–3300 m, inland
3 C. abrupta
                      47' Fruit filling > 1/2 perigynium body; perigynium front veins 0–4(6), generally < 1/2 fruit length, sometimes > fruit, beak < or > 2/5 perigynium length, perigynium not boat-shaped, wings not incurved to front; 0–3500 m, coastal or inland
 
                        48. Perigynium green or brown, margin green, flat margin including wing < 0.3 mm wide; fruit filling 1/2–2/3 perigynium body; lowest spikelet bract bristle- or leaf-like
2 C. harfordii
                        48' Perigynium dark gold to brown, metallic, upper margin sometimes green, flat margin including wing 0.2–0.5 mm wide; fruit filling 2/3–4/5 perigynium body; lowest spikelet bract generally like pistillate flower bract
2 C. pachystachya
                    46' Lowest 2 inflorescence internodes together > 1/3 inflorescence length
 
                      49. Pistillate flower bract generally ± > 3.5 mm
 
                        50. Perigynium body flat or ± planoconvex, beak tip red with white flap along middle of back; leaf blade 0.5–2.5 mm wide; 2700–3900 m, inland
5 C. phaeocephala
                        50' Perigynium body planoconvex, beak tip green to red-brown; leaf blade 1.3–4.5 mm wide; 0–3200 m, coastal or inland
 
                          51. Perigynium sometimes boat-shaped, wings incurved to front, front veins (2)4–8, thin, > fruit; base of at least lowest spikelet generally long-tapered
3 C. mariposana
                          51' Perigynium not boat-shaped, wings not incurved to front, front veins 0 or few, thick, generally < fruit; spikelet base generally ± round to wedge-shaped
 
                            52. Perigynium wall delicate, beak tip to fruit top (1.8)2.4–3.7 mm; spikelets generally distinct; lowest spikelet bract < or > lowest spikelet, like pistillate flower bract or bristle-like; stem self-supported; 30–3000 m, ± inland
6 C. preslii
                            52' Perigynium wall ± tough, beak tip to fruit top 1.5–2.5 mm; upper spikelets generally indistinct; lowest spikelet bract > lowest spikelet, bristle- or leaf-like; stem often supported by vegetation; < 900 m, coastal
3 C. subbracteata
                      49' Pistillate flower bract generally ± < 3.5 mm
 
                        53. Perigynium front veins (2)4–8, thin, > fruit; base of at least lowest spikelet generally long-tapered
3 C. mariposana
                        53' Perigynium front veins 0–few, thick, generally < fruit; spikelet base generally ± round to wedge-shaped
 
                          54. Fruit 1–1.6 mm, 0.7–1.2 mm wide; perigynia appressed to spreading, generally < 3.5 mm, flat margin including wing generally < 0.2 mm wide, beak tip light to medium brown; spikelet fine-textured (parts small)
3 C. subfusca
                          54' Fruit 1.4–2.2 mm, 1–1.5 mm wide; perigynia ± spreading, often > 3.5 mm, flat margin including wing generally > 0.2 mm wide, beak tip generally dark brown; spikelet coarse-textured (parts large)
 
                            55. Pistillate flower bract generally reddish to brown ± throughout; perigynium ± = pistillate flower bract in color, back only generally bulged, upper margin dark brown, coppery, or narrowly green to gold, beak tip to fruit top 1.5–2.9 mm; fruit body generally 1.4–1.7 (1.2–2.2) mm, ovate; spikelets generally > 5, not or only lower distinct; inflorescence 9–24 mm
2 C. pachystachya
                            55' Pistillate flower bract brown to gold, center green; perigynium not = pistillate flower bract in color, front and back generally bulged, upper margin widely green to gold, beak tip to fruit top (1.8)2.4–3.7 mm; fruit generally 1.7–2.1(1.5–2.3) mm, ± squared; spikelets 3–7, ± distinct; inflorescence 17–25 mm
6 C. preslii


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