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Key to Carex, [26rr] Section 31 Lupulinae: section Lupulinae

Cyperaceae

Carex

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© Kristie Gianopulos
1 Sheath of uppermost leaf absent or < 1.5 (-2.5) cm long; beaks of perigynia 1.5-4.2 mm long, < 1/3 the length of the entire perigynium; teeth at tip of perigynium beak with > 10 scabrules on inner side; achenes with elliptic or obovate sides; achene surfaces papillose at 50× magnification; plants densely cespitose, never with elongate rhizomes; [subsection Intumescentes].
  2 Perigynia rhombic-ovoid, with cuneate bases, 8-35 per spike, radiating in all directions and therefore forming a globular spike; perigynia dull when dry
  2 Perigynia lanceoloid to ovoid, with rounded bases, 1-12 (-20) per spike, ascending to spreading (the lowest sometimes slightly reflexed) and therefore forming an ovoid to obovoid spike; perigynia lustrous when dry.
    3 Perigynia 3-5 mm wide at the widest point; achenes broadest above the middle, with a pronounced shoulder rounding abruptly to the tip; style of mature achene with a half to full coil in its lower portion; [of high elevations in our area, generally in spruce-fir or northern hardwoods forests]
    3 Perigynia 5-8 mm wide at the widest point; achenes broadest at the middle, smoothly rounded to the tip; style of mature achene straight or arcuate; [widespread in our area]
1 Sheath of uppermost leaf usually > 1.7 cm long; beaks of perigynia 4.5-10 mm long, generally > 1/2 the length of the entire perygynium; teeth at tip of perigynium beak with < 5 scabrules on inner side; achenes with rhombic or nearly triangular sides; achene surfaces smooth at 50× magnification; [subsection Lupulinae].
      4 Base of lowest staminate spike overtopping the tip of the pistillate spikes by 2.3-7.5 cm in the longest culms; mature achenes (1.5-) avg. 1.8 (-2.0) mm wide, mostly flat‐sided in cross‐section; leaves 3-5 mm wide; plants always long‐rhizomatous, forming extensive patches
      4 Base of the lowest staminate spike overlapping with the pistillate spikes or overtopping them by < 2.2 cm in the longest culms; mature fruits (1.9-) avg. 2.6 (-3.8 mm wide, concave in cross‐section (rarely flat‐sided in C. lupulina); leaves 3-12 mm wide; plants cespitose to long‐rhizomatous.
        5 Achene body (2.8-) avg. 3.3 (-3.7) mm long, (1.1-) avg. 1.4 (-1.7) × as long as wide; achene edges without distinct knobs or acute upturned angles, the outline smoothly curved without an inflexion point; achene length at 1/8th the width > 1.10 mm; perigynia densely arrayed in the spikes (except for depauperate individuals), (12-) avg. 17 (-24) perigynia per cm in the middle of the spike, these spreading at an angle of (40-) avg. 50 (-70) degrees from the vertical
        5 Achene body (1.9-) avg. 2.6 (-–3.1) mm long, (0.7-) avg. 1.0 (-1.2) × as long as wide; achene edges with distinct knobs or acute upturned angles (often rounded in C. gigantea but then the achene bodies clearly wider than long); achene length at 1/8th the width < 1.10 mm, perigynia less densely arrayed in the spikes, (6.6- avg. 13 (-18) perigynia per cm, these spreading at an angle of (45-) avg. 60 (-90) degrees from the vertical.
          6 Perigynia green with a slight orange tinge when mature, spreading at an angle of (45-) avg. 60 (-70) degrees from the vertical; perigynium body (excluding the border of the stigma aperture) with (2.9-) avg. 15 (-30) scabrules; distance between the apex of the achene body and the start of the style curve (0.2-) avg. 0.6 (-1.2) mm
          6 Perigynia green when mature, drying brown and without an orange tinge, these spreading at an angle of (60-) avg. 80 (-90) degrees from the vertical; perigynium body with (0-) avg. 0.2 (-3) scabrules; distance between the apex of the achene body and the start of the style curve (1.1-) avg. 1.6 (-2.3) mm (or the style rarely straight in C. gigantea).
             7 Widest leaf (3-) avg. 5.5 (-7.5) mm wide; perigynium gradually narrowed into a beak, (1.3-) 1.4–2.8 (-3.2) mm wide at half its length; achene body length at 1/8th of its width 25-37% of total length of achene body; longest pistillate spike with (11-) avg. 16 (-27) perigynia; plants strictly long‐rhizomatous
             7 Widest leaf (5.5-) avg. 12 (-13) mm wide; perigynium abruptly narrowed into the beak, (0.5–) 0.7-1.4 (-1.6) mm wide at half its length; achene body length at 1/8th of its width (32-) 35-50 (-52)% of the total length of the achene body; longest pistillate spike with (25-) avg. 38 (-65) perigynia; plants cespitose to long‐rhizomatous