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Key to Carex, [26r] Section 13 Phacocystis: section Phacocystis (Cryptocarpae and Acutae)

Cyperaceae

Carex

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1 Lowest spike erect or ascending.
  2 Lower sheaths scabrous, reddish-brown, the sheath fronts (ventral faces) with prominent veins forming a persistent network; lower sheaths usually bladeless
  2 Lower sheaths glabrous, the sheath fronts (ventral faces) not forming a persistent network; lower sheaths usually with leaf blades.
    3 Perigynia evidently nerved on both faces
      4 Pistillate scales (at least the lowermost) with a prominent, scabrous awn
    3 Perigynia not nerved, or very faintly nerved.
        5 Longest bracts overtopping the spikes; perigynia flattened, elliptic to obovate; pistillate scales acute to obtuse, generally shorter than the perigynia
1 Lowest spike pendent.
          6 Pistillate scales awnless, the sides black or deep purple-brown; perigynia usually divergent, with apices often slightly reflexed at maturity
          6 Pistillate scales awned, the sides dark reddish-brown, light golden-brown, tan, or clear; perigynia divergent or ascendent, the apices straight or slightly reflexed at maturity.
             7 Sheath backs glabrous [prickles 0-1 (-5) per mm2 of sheath surface 5 cm from base]; perigynia somewhat inflated, obovoid, rounded above to an abrupt beak; lowest bract of the infructescence 17-62 cm long.
               8 Perigynia strongly obovoid, 3-4.5 mm long, 2-3 mm wide; achene symmetrical
               8 Perigynia ellipsoid to slightly obovoid, 2-3 (-3.5) mm long, 1-2 mm wide; achene usually shortened on one side, slightly to strongly asymmetrical
             7 Sheath backs scabrous [prickles (1-) 5-54 per mm2 of sheath surface 5 cm from base]; perigynia flattened, elliptic to ovoid, tapering from near or below the middle to a minute beak; lowest bract of the infructescence 7-35 cm long.
                 9 Perigynia densely granular-papillose throughout, the papillae mostly > 13 μm long; lower pistillate scales usually truncate or retuse, abruptly awned; sheaths finely scabrous; achenes not constricted when at maturity; [more commonly in the piedmont and coastal plain but also scattered inland]
                 9 Perigynia smooth to slightly papillose toward the apex, the papillae mostly < 10 μm long; lower pistillate scales usually acute or acuminate, tapering into the awn; sheaths strongly scabrous; [primarily montane in distribution southward (C. fumosimontana), or montane southward and more commonly in a variety of wetlands northward (C. gynandra)].
                   10 Pistillate and staminate scale bodies dark reddish-brown; apex of pistillate scale bodies retuse with rounded shoulders, the awn extending from the notch; sheath faces with reddish-brown prickles; widest leaves per plant (3-) 4.5-6.5 (-8) mm wide; longest proximal spikes (29-) 42-60 (-76) mm long; longest distal spikes (20-) 29-40 (-48) mm long
                   10 Pistillate and staminate scale bodies clear, tan, or light golden-brown; apex of pistillate scale bodies acuminate to rounded (or rarely obliquely truncate) into the awn base; sheath faces with colorless prickles; widest leaves per plant (5-) 6.5-10.5 (-14) mm wide; longest proximal spikes (35-) 51-93 (-125) mm long; longest distal spikes (20-) 33-58 (-82) mm long