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1 Apex of perigynium beak terminated by 2 teeth, mostly > 0.5 mm long. |
2 Perigynia > 4× as long as wide (8-15 × 1-3 mm). |
3 Apical teeth of perigynium beak erect; achenes oblong- obovoid or obovoid; at least proximal pistillate scales with 3-5 (-7)-veined center |
3 Apical teeth of perigynium beak reflexed; achenes elongate; pistillate scales with 1-veined center |
2 Perigynia < 4× as long as wide. |
4 Perigynia > (9-) 10 mm long. |
5 Sheaths, at least the proximal sheath fronts, densely tomentose at mouth; apical teeth of perigynium beak often > 1 mm long |
5 Sheaths glabrous; apical teeth of perigynium beak not more than 1 mm. |
6 Perigynia 7-11-, 5-12-, or 12-25-veined |
6 Perigynia 12-34-veined. |
7 Basal and proximal leaf sheaths reddish or purplish |
7 Basal and proximal leaf sheaths yellowish to brown, without trace of red or purple |
4 Perigynia < 10 mm long. |
8 At least proximal pistillate scales with long, rough awn. |
9 Perigynia with 2 strong marginal veins, otherwise veinless or veined only proximally; leaves not septate- nodulose. |
9 Perigynia with 5+ strong veins extending length of bodies; leaves septate- nodulose. |
10 Perigynium beak with apical teeth (0.4-) 0.6-3 mm long, often > 1 mm long |
10 Perigynium beak with apical teeth < 1 mm long. |
11 Perigynium body obovoid, widest distally; proximal bract > 3× as long as the inflorescence |
11 Perigynium body ovoid or lanceoloid or ellipsoid, widest at middle or proximally; proximal bract usually < 2× as long as the inflorescence. |
12 Perigynium beak 0.9-1.7 mm long; mature perigynia dull |
12 Perigynium beak 0.2-6 mm long; mature perigynia somewhat glossy |
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13 Culms with some red or purple at base. |
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14 At least proximal perigynia in each spike spreading or reflexed; leaves sparsely septate- nodulose |
13 Culms brown or black at base, without trace of red or purple. |
15 Pistillate scales with 5-7-veined center |
15 Pistillate scales with 1-3-veined center. |
16 Leaves not septate- nodulose |
16 Leaves at least sparingly septate- nodulose |
1 Apex of perigynium beak entire, emarginate, or with teeth mostly < 0.5 mm long. |
17 Leaf blades variously hairy. |
18 Plant brown or black at base |
18 Plant with at least some red or purple at base |
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19 Bracts without blades. |
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20 Leaves much wider, often over 10 mm wide |
19 Bracts, at least the proximal, with distinct blade. |
21 Young leaves V-shaped or rounded in cross section, adaxial surface without 2 marginal veins more prominent than midvein or other veins. |
22 Perigynium beak with 2 distinct terminal teeth, usually > 0.2 mm long. |
23 At least proximal pistillate scales awned, awn at least 1/2 as long as body; leaves conspicuously septate- nodulose. |
24 Base of culm strongly red or purple; leaves 2-4 mm wide |
24 Base of culm brown, without or with only trace of red or purple; leaves 4-15 mm wide. |
25 Distal pistillate scales acute, acuminate, or short-awned, awn less than 1/2 length of body |
25 Distal pistillate scales with awn at least about as long as body |
23 Pistillate scales obtuse to acuminate, sometimes very shortly awned; leaves not or only weakly septate- nodulose. |
26 Plants with long-creeping rhizomes; leaves usually not septate- nodulose |
26 Plants with short- ascending rhizomes; leaves at least sparingly septate- nodulose. |
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22 Perigynium beak entire, emarginate, or with 2 apical teeth < 0.2 mm long. |
28 Perigynia rounded at base, sides proximally distinctly convex. |
29 Perigynia with veins slightly prominent |
29 Perigynia with veins slightly impressed |
28 Perigynia tapering at base, sides straight or only slightly convex proximally. |
30 Perigynia rounded at apex, beakless or with beak < 0.3 mm long. |
31 Widest leaf blades < 5 mm wide; plants usually not cespitose |
31 Widest leaf blades usually > 5 mm wide; plants usually cespitose |
30 Perigynia tapering to beak at least > (0.3-) 0.5 mm long. |
32 Proximal perigynia in each spike spreading at right angles or reflexed at maturity; leaves and sheaths sparsely septate- nodulose |
32 Proximal perigynia in each spike ascending or spreading- ascending; leaves and sheaths not septate- nodulose. |
33 Plants usually colonial; perigynia and leaves often papillose |
33 Plants cespitose; perigynia and leaves not papillose |
21 Leaf blades M-shaped in cross section when young, adaxial surface with 2 marginal veins more prominent than midvein and other marginal veins, sometimes apparent only on proximal leaves and on proximal part of blade. |
34 Perigynium beakless or with beak < 0.5 mm long, entire or with 2 apical teeth < 0.1 mm long. |
35 Widest leaf blades (usually basal) > 10 mm wide. |
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36 Distal pistillate spikes erect, perigynia < 30 per spike; [native]. |
37 Perigynia trigonous with rounded angles in cross section |
37 Perigynia sharply trigonous in cross section |
35 Widest leaf blades < 10 mm wide. |
38 Perigynia not prominently veined, veins somewhat impressed |
38 Perigynia at least slightly prominently veined or veinless except for 2 marginal veins. |
39 Perigynia rounded at base, sides proximally convex |
39 Perigynia tapering at base, sides proximally straight, concave or slightly convex. |
40 Perigynia transversely wrinkled; leaf sheaths sparsely septate- nodulose |
40 Perigynia not transversely wrinkled; leaf sheaths not septate- nodulose. |
41 Perigynia sharply trigonous in cross section |
41 Perigynia terete or with rounded angles in cross section. |
42 Perigynia with 2 marginal veins and not more than 10 veins on faces |
42 Perigynia with more than 12 veins. |
43 Plants usually colonial, not cespitose; perigynia papillose at least faintly. |
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34 Perigynium with distinct beak > 0.5 mm, usually with apical teeth > 0.1 mm long. |
44 Perigynia with 2 distinct marginal veins, otherwise veinless or with very weak veins proximally. |
45 Perigynium beak entire, emarginate, or with apical teeth < 0.1 mm long |
45 Perigynium beak with apical teeth 0.2-1 mm. |
46 Perigynium beak usually < 1 mm long. |
46 Perigynium beak sometimes > 2 mm long |
44 Perigynia with more than 2 veins extending most of length of bodies. |
47 Pistillate scales with narrow, indistinct bodies, scarcely enlarged at bases |
47 Pistillate scales with wide, flat bodies, sometimes terminating in awns. |
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49 Perigynium with not more than 5 veins extending length of body on abaxial face, veinless or weakly veined on adaxial face |
49 Perigynium with > 8 equally prominent veins on both faces. |
50 Perigynia bluntly angled in cross section |
50 Perigynia sharply angled in cross section |
48 Perigynium beak with 2 distinct teeth at apex, usually > 0.2 mm long. |
51 Pistillate spikes, at least the proximal, lax, proximal and middle perigynia separated by internodes at least 1/4 their length; leaves and sheaths not septate- nodulose |
51 Pistillate spikes dense, proximal and middle perigynia separated by internodes less than 1/10 their length; proximal leaves and sheaths sparingly septate- nodulose. |
52 Pistillate scales, at least proximal, awned, awn at least 1/4 of scale body length. |
53 Distal pistillate scales acuminate or with awn less than 1/2 body length; staminate spikes usually 2+ |
53 Distal pistillate scales awned, awn usually more than 1/2 body length; staminate spikes 1, sometimes with 1 much smaller spike laterally |
52 Pistillate scales obtuse to acute or apiculate, apiculus not more than 1/10 of body length. |
54 Culms purple-red at base; achenes with style persistent |
54 Culms brown at base, without trace of red or purple; achenes with style deciduous |