The Jepson Manual: Higher Plants of California

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Names are linked to treatments from the Manual


Key to SCIRPUS

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

  1. Spikelets generally 1(3), ± sessile; stem and leaf blade << 1.5 mm wide
 
    2. Plant submersed except inflorescence, leaf tip generally floating; spikelet 6–13 mm
S. subterminalis
    2' Plant terrestrial or emersed, leaf tip not floating; spikelet 2–7 mm
 
      3. Largest spikelets generally < 6-flowered; fruit smooth; High Sierra Nevada, > 2400 m
 
        4. Rhizome 0; fruit sharply 3-angled; inflorescence bract > spikelet, tip with awn generally > 1 mm
S. clementis
        4' Rhizome slender; fruit compressed, 2–3-angled; inflorescence bract < spikelet, tip abruptly pointed
S. pumilus
      3' Largest spikelets generally > 8-flowered (except some S. cernuus); fruit generally papillate, pitted, or ribbed; w of High Sierra Nevada, < 1500 m
 
        5. Flower bract strongly keeled throughout, ± folded in fruit; fruit sides concave to ± flat, fine-papillate
S. koilolepis
        5' Flower bract keeled above middle, ± flat in fruit; fruit sides convex, ribbed or fine-papillate to -pitted
 
          6. Fruit sharply 3-angled, sides fine-papillate or -pitted; rhizome 0; spikelet 1
S. cernuus
          6' Fruit obscurely 3-angled, sides ribbed; rhizome thread-like; spikelets 1–3
S. setaceus
  1' Spikelets generally 2–many, sessile or stalked; stem and leaf blade (0.6)2–15 mm wide (stem generally < 1 mm wide in S. nevadensis and S. saximontanus)
 
    7. Annual; rhizome 0; stem generally < 1 mm wide; fruit sharply transverse-ribbed
S. saximontanus
    7' Perennial; rhizome short to long; stem (0.6)2–15 mm wide; fruit smooth (low-ridged in S. mucronatus)
 
      8. Well developed inflorescence bracts generally 2+, thin, leaf-like, generally spreading; leaves ± cauline, blades generally > sheaths, thin
 
        9. Spikelet 1–3.5 mm wide; fruit ± 0.5–2 mm; flower bract glabrous, tip acute to abruptly pointed; tubers 0
 
          10. Spikelets not clearly clustered, ± stalked
S. pendulus
          10' Spikelets mostly in head-like clusters, sessile
 
            11. Fruit generally 2-angled; stigmas 2; perianth bristles straight in fruit, fine-toothed throughout
S. microcarpus
            11' Fruit 3-angled; stigmas generally 3; perianth bristles ± contorted to straight in fruit, fine-toothed above middle
 
              12. Flower bract dark brown to blackish in fruit; perianth bristles < 4 mm, teeth sparse, ascending
S. congdonii
              12' Flower bract brown in fruit; perianth bristles generally < 2.5 mm, teeth dense, reflexed
S. diffusus
        9' Spikelet 4–10 mm wide; fruit 2–4.5 mm; flower bract scabrous or sparse-puberulent, tip awned; tubers generally present
 
          13. Perianth bristles persistent on fruit; fruit sharply 3-angled, sides ± concave; longest inflorescence bract generally 4–15 mm wide when dry; leaf blade generally 6–20 mm wide when dry; stigmas 3
S. fluviatilis
          13' Perianth bristles generally not persistent on fruit; fruit ± weakly 2–3-angled, sides convex; longest inflorescence bract generally 2–6 mm wide when dry; leaf blade generally 2–12 mm wide when dry; stigmas 2–3
 
            14. Spikelet 4–5 mm wide; fruit 2–2.5(3) mm; stigmas 3
S. tuberosus
            14' Spikelet 5–10 mm wide; fruit (2.5)3–3.5 mm; stigmas 2–3
 
              15. Flower bract not strongly appressed, ± pale grayish to orange-brown; spikelets often in 1 dense cluster; leaf sheath top opposite blade with a triangular, veinless area
S. maritimus
              15' Flower bract strongly appressed, ± orange-brown; spikelets generally on open, elongate branches; leaf sheath top opposite blade clearly veined
S. robustus
      8' Well developed inflorescence bract generally 1, thick, ± stem-like at least above, erect or bent to side; leaves ± basal; blades 0 or generally < sheaths (except S. nevadensis, S. pungens), thin to stem-like
 
        16. Stem 3-angled, at least above
 
          17. Inflorescence panicle-like, dense to open, spikelets 20–many; perianth bristles on fruit thick, flat, fringed with soft hairs; stem often cylindric below, < 4 m
S. californicus
          17' Inflorescence head-like, or rarely with 1–2 short branches, spikelets 1–12(20); perianth bristles on fruit slender, minutely spiny; stem 3-angled throughout, generally < 2.2 m
 
            18. Leaf blade vestigial or 0; inflorescence bract generally bent to side; flower bract tip abruptly pointed, notch 0; fruit low-ridged; rhizome short, obscured by crowded stems
S. mucronatus
            18' Leaf blade < to > sheath; inflorescence bract generally erect; flower bract tip awned from notch; fruit smooth; rhizome long, not obscured
 
              19. Flower bract tip with awn < 0.5 mm; uppermost leaf blade generally < sheath; stem sides deep-concave
S. americanus
              19' Flower bract tip with awn 0.5–1.5 mm; uppermost leaf blade > sheath; stem sides ± flat to shallow-concave
S. pungens
        16' Stem cylindric throughout
 
          20. Inflorescence head-like; spikelets 1–10; flower bract tip acute to obtuse, notch 0
S. nevadensis
          20' Inflorescence panicle-like; spikelets 3–100+; flower bract tip short-awned, notched (tip sometimes worn off in age)
 
            21. Spikelets solitary at branch tips; fruit 3-angled, 2.5–3 mm, beak 0.3–1 mm; stigmas 3
S. heterochaetus
            21' Spikelets many, mostly clustered at branch tips; fruit ± 2–3-angled, ± 2–2.5 mm, beak 0.1–0.4 mm; stigmas 2–3
 
              22. Flower bract generally prominently spotted, awn generally contorted, 0.5–1 mm; spikelets generally 1–7 per cluster
S. acutus var. occidentalis
              22' Flower bract faintly spotted or not, awn ± straight, generally < 0.5 mm; spikelets generally solitary or 2–3 per cluster
S. tabernaemontani


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