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| 1 Leaf sheath fronts yellow, thickened, and not fragile at the top; leaf blades papillose adaxially (at 25× magnification) |
| 1 Leaf sheath fronts green or whitish, thin, and fragile at the top; leaf blades not papillose adaxially. |
| ..2 Leaf sheath fronts smooth. |
| ....3 Larger perigynia 6-8 mm long; leaves to 12 mm wide |
| ....3 Larger perigynia 3-5 mm long; leaves to 7 mm wide. |
| ......4 Perigynia smoothly rounded at base, not distended; perigynium veins 3-5 abaxially, 0 adaxially |
| ......4 Perigynia cordate at base, distended; perigynium veins 10-12 abaxially, 7 adaxially |
| ..2 Leaf sheath fronts rugose. |
........5 Perigynia broadly rounded at base, not distended; perigynium veins 3-5 abaxially, 0 adaxially |
| ........5 Perigynia cordate or truncate at base, distended; perigynium veins 15 abaxially, 7 adaxially. |
| ..........6 Perigynia (5-) avg. 5.4 (-6) mm long, the beak > 3 mm long; larger leaves mostly 8-17 mm wide; perigynium scales cuspidate to short-awned; [mostly of the Coastal Plain and lower Piedmont] |
| ..........6 Perigynia (4-) avg. 4.7 (-5) mm long, the beak < 2.5 mm long; larger leaves mostly 4-10 mm wide; perigynium scales acuminate to cuspidate; [widespread in our area] |
| 1 Beak of the perigynium shorter than the body. |
..2 Perigynia somewhat abruptly contracted into a beak ca. 0.5 × as long as the perigynium body; ventral surface of the perigynium with several incomplete veins basally; culms sharply triangular and narrowly winged, somewhat spongy and easily crushed; dorsal leaf sheaths green; ventral leaf sheaths with scattered red dots, and transversely rugose; [normally of shaded locations] |
| ..2 Perigynia tapering into a beak, much shorter than the perigynium body; ventral surface of the perigynium with several inconspicuous complete veins; culms inconspicuously triangular to roundish, not winged, neither spongy nor easily crushed; dorsal leaf sheaths dark blue-green with conspicuous white dots; ventral leaf sheaths without scattered red dots, not transversely rugose; [normally of sunny locations] |
| 1 Beak of the perigynium as long as, or longer than, the body. |
| ....3 Ventral leaf sheath margins with orange-red dots; achene ovate-lanceolate; perigynium wall adhering to achene |
| ....3 Ventral leaf sheath margins without orange-red dots; achene broadly ovate to ovate-orbicular; perigynium wall not adhering to the achene (or only slightly so). |
| ......4 Ventral leaf sheaths not transversely rugose, more or less concave at the apex and not prolonged upward past the base of the blade, thickened, not friable |
| ......4 Ventral leaf sheaths transversely rugose, more or less convex at the apex and prolonged upward past the base of the blade, friable. |
| ........5 Perigynia (5-) avg. 5.4 (-6) mm long, the beak > 3 mm long; larger leaves mostly 8-17 mm wide; perigynium scales cuspidate to short-awned; [mostly of the Coastal Plain and lower Piedmont] |
| ........5 Perigynia (4-) avg. 4.7 (-5) mm long, the beak < 2.5 mm long; larger leaves mostly 4-10 mm wide; perigynium scales acuminate to cuspidate; [widespread in our area] |