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2 Leaf sheaths scabrous to hispidulous; perigynium beak (0.5-) 0.6-1.3 mm long |
3 Leaf blades, especially of overwintered leaves, glaucescent, papillose abaxially; perigynia (3.7-) 4.0-4.7 (-5.1) × 1.5-1.7 (-1.8) mm; longest terminal spikes (25-) 30-46 mm long; [of the Cumberland Plateau of n. AL] |
3 Leaf blades green, glabrous abaxially or sparsely hispidulous; perigynia (4.5-) 4.6- 5.6 (-6.2) × 1.9-2.2 (-2.3) mm; longest terminal spikes 14-34 (-42) mm long; [of ne. United States, south in our area to w. NC and w. VA] |
2 Leaf sheaths glabrous; perigynium beak 0-0.5 (-0.7) mm long |
4 Leaf blades glaucous; pistillate scales awnless or awn < 1 (-1.9) mm long. |
5 Perigynia (4.0-) 4.2-5.5 (-6.0) mm long; achene bodies 0.37-0.5× as long as the perigynia; pistillate spikes (5-) 5.7-8 (-9.6) mm wide; achene beak straight to bent less than 30° from the vertical |
5 Perigynia 3.2-4.5 (-4.7) mm; achene bodies 0.5-0.63 (-0.67)× as long as the perigynia; pistillate spikes (3.3-) 4.2-6.1 (-7.3) mm wide; achene beak usually bent 30-90° from vertical. |
6 Perigynia 3.2-4.0 (-4.1) mm long, (1.5-) 1.8-2.3 (-2.5)× as long as wide; longest pistillate spike with (14-) 19-45 (-65) flowers, densely flowered, with the ratio [mm of spike length/number of flowers] = (0.56-) 0.67-1.1 (1.3); longest peduncle of staminate spike 0.5-15 (-31) mm long |
6 Perigynia (3.7-) 3.9-4.5 (-4.7) mm long, (1.9-) 2.1-2.6 (-2.8)× as long as wide; longest pistillate spike with 11-25 (-28) flowers, rather loosely flowered, with the ratio [mm of spike length/number of flowers] = (0.97-) 1.0-1.3 (1.6); longest peduncle of staminate spike (1.5-) 7.5-37 (-62) mm long |
4 Leaf blades deep or light green; pistillate scales usually with awns (0-) 1.2-3.7 (-6) mm long. |
7 Peduncles of lateral spikes scaberulous; perigynia (6-) 18-37 (-86) per spike; perigynia (2.5-) 2.8-3.6 (-4.3) mm long, 17-25-veined |
7 Peduncles of lateral spikes glabrous or scaberulous; perigynia (3-) 5-16 (-19) per spike; perigynia (3.6-) 4-5 (-5.5) mm long, 40-65-veined |
8 Widest leaf blades 2.6-4.0 mm wide; ligules of proximal bracts 0.4-1.8 (-3.6) mm long; perigynium apex bent; achene beaks bent |
8 Widest leaf blades (3.7-) 4.2-8.2 (-9.1) mm wide; ligules of proximal bracts (1.8-) 4.0-10.7 (-12.9) mm long; perigynium apex straight; achene beaks straight. |
9 Perigynia obtusely triangular in cross section, (2.2-) 2.5-3.1 × as long as wide, 1.5-1.9 (-2.2) mm wide; achenes (1.3-) 1.5-1.7 (-1.8) mm wide; achene stipes (0.3-) 0.4-0.6 mm long |
9 Perigynia orbicular to suborbicular in cross section, 1.8-2.3 (-2.6)× as long as wide, (1.8-) 2-2.6 mm wide; achenes 1.7-2.1 (-2.2) mm wide; achene stipes (0.2-) 0.3-0.4 (-0.5) mm long |
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10 Plants not cespitose; rhizome internodes 2-3.4 mm thick; terminal spikes (2.8-) 3.3-4.5 (-5.4) mm wide, usually much exceeding the distal bract |
10 Plants cespitose; rhizome internodes 1.2-2.2 mm thick; terminal spikes (0.9-) 1.3-2.9 (-3.1) mm wide, usually much exceeded by the distal bract |
11 Perigynia spirally imbricate; proximal bracts with sheaths loose; ligules (0.9-) 2-12.9 mm |
12 Culm bases with purple-red to (3.4-) 4.0-7.3 cm high; widest leaf blades 2.4-4.0 (-5.3) mm wide; achene stipes 0.6-0.8 (-0.9) mm long |
12 Culm bases with purple-red to 0.3-2.4 (-7.3) cm high; widest leaf blades 3.3-8.0 (-9.1) mm wide; achene stipes (0.2-) 0.3-0.6 mm long. |
13 Perigynia (1.8-) 2.0-2.6 mm wide, orbicular to suborbicular in cross section; achene bodies (2.6-) 3.1-3.5 (-3.7) mm long; achene stipes (0.2-) 0.3-0.4 (-0.5) mm; achene bodies 4.8-9.7 (-12)× as long as the stipes |
13 Perigynia 1.5-2.3 (-2.4) mm wide, obtusely triangular in cross section; achene bodies 1.8-2.3 (-2.4) mm long; achene stipes (0.3-) 0.4-0.6 mm; achene bodies 3.2-5.8 (-7.3)× as long as the stipes. |
14 Perigynia 4.2-5.0 (-5.2) × 1.5-1.9 (-2.2) mm, (2.2-) 2.5-3.1× as long as wide; achene bodies broadly obovoid to oblong- obovoid, widest at a point 0.55-0.67 (-0.70) from base to tip of body |
14 Perigynia (3.6-) 3.9-4.5 (-4.7) × (1.7-) 1.8-2.3 (-2.4) mm, 1.8-2.3 (-2.5)× as long as wide; achene bodies broadly obdeltoid- obovoid, widest at a point (0.6-) 0.65-0.80 from base to tip of body |
11 Perigynia distichously imbricate; proximal bracts with sheaths tight; ligules 4-4.9 (-9.6) mm (to 2.2 mm in C. bulbostylis). |
 Show caption*© Aidan Campos, some rights reserved (CC BY-NC), uploaded by Aidan Campos much inflated, orbicular or suborbicular in cross section, (1.8-) 2.0-2.5 (-2.8) mm wide, 1.6-2.0 (-2.1)× as long as wide |
15 Perigynia tightly enveloping achene or slightly inflated, obtusely triangular in cross section, 1.4-2.1 (-2.3) mm wide, (1.7-) 2.1-3.3× as long as wide. |
16 Plants loosely cespitose; longer rhizome internodes 7-58 mm long |
16 Plants densely cespitose; longer rhizomes internodes 0.2-6 (-8) mm long. |
17 Proximal bracts with bases of blades white between veins (most easily seen on abaxial surface) |
17 Proximal bracts with bases of blades uniformly green |
18 Perigynia (1.7-) 2.1-2.6× as long as wide, apex usually abruptly contracted; beak (0.3-) 0.5-1.2 mm long; longest lateral spike with 2-8 (-10) perigynia (including undeveloped or aborted ones) |
19 Proximalmost spike usually considerably beyond base of culm; longest vegetative shoot 0.88-1.4× as long as the longest culm; proximal bracts with sheath front convex and elongated (0.8-) 1.1-4.0 mm beyond apex |
19 Proximalmost spike usually basal; longest vegetative shoot (0.8-) 1.4-4.4× as tall as the culms; proximal bracts with sheath front apices concave or truncate. |
20 Culm bases with purple-red extending 2.7-5.2 (-5.6) cm; bodies of pistillate scales (2.2-) 2.5-3.0 mm long; achene beaks (0.1-) 0.2-0.3 mm long |
20 Culm bases with purple-red extending (3.7-) 4.7-11.7 cm; bodies of pistillate scales 1.5-2.1 (-2.5) mm long; achene beaks 0.05-0.10 (-0.15) mm long |
18 Perigynia (2.4-) 2.5-3.3× as long as wide, apex gradually tapering; beakless or the beak 0.1-0.4 mm; longest lateral spike with (5-) 7-14 perigynia (including undeveloped or aborted ones) |
21 Perigynia (1.9-) 2.0-2.3× as long as the achene bodies; achene beaks (0.3-) 0.4-0.7 mm long |
21 Perigynia 1.7-2.0× as long as the achene bodies; achene beaks 0.1-0.3 (-0.4) mm long. |
22 Longest (per plant) peduncle of terminal spike 0.9-3.2 (-6.8) cm long; two distalmost lateral spikes usually overlapping; longest vegetative shoot 1.4-2.2× as tall as the longest culm |
22 Longest (per plant) peduncle of terminal spike (2.2-) 5.1-8.9 (-10.4) cm long; two distalmost lateral spikes usually widely separate or occasionally overlapping; longest vegetative shoot 0.5-1.3× as tall as the longest culm |