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1 Perigynia surfaces and beak often pubescent, finely papillate |
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2 Lateral spikes usually pedunculate; lowermost inflorescence bracts sometimes with sheath; peduncles with prophyll at base. |
3 Terminal spike gynecandrous, pistillate flowers as many as or more numerous than staminate; lateral spikes short, not much longer than wide; fresh perigynia white- pulverulent |
3 Terminal spike usually staminate or, sometimes, gynecandrous, staminate flowers then more numerous than pistillate; lateral spikes oblong, distinctly longer than wide; fresh perigynia green or slightly glaucous. |
4 Pistillate scales (at least the lower) long-awned |
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5 Perigynia often papillose over most of the surface; style deciduous |
2 Lateral spikes sessile; bracts sheathless; peduncles without (or rarely with) a prophyll |
6 Perigynia papillose (visible at 20× magnification). |
7 Terminal spike staminate, androgynous, or gynecandrous (if gynecandrous, the staminate flowers more numerous than the pistillate); lateral spikes at least 2× as long as wide |
7 Terminal spike staminate or gynecandrous (if gynecandrous, the pistillate flowers more numerous than the staminate); lateral spikes not much longer than wide |
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12 Margins of perigynia flat, at least in the upper ½, flat portion (measured at the tip of the achene and base of beak) > (0.1-) 0.2 mm wider |
13 Achenes rounded at apex ( style dehiscing at the surface of the achene); style conspicuously enlarged at the base |
13 Achenes with short apiculus formed by the persistent base of the style; style not conspicuously enlarged at base |
12 Margins of perigynia rounded, or with flat portion < 0.1 mm wide. |
14 Margins of perigynia rounded or with a very narrow rounded edge; achenes nearly filling the perigynium bodies |
14 Margins of perigynia sharply edged or narrowly winged; achenes distinctly smaller than the perigynium bodies. |
15 Inflorescences in fruit 1-1.5× as long as wide |
15 Inflorescences in fruit 1.5-2 (or more)× as long as wide. |
16 Lowermost perigynia in each spike spreading |
16 Lowermost perigynia in each spike ascending or erect. |
17 Perigynium serrulate on the margins of the upper body and lower beak |
17 Perigynium entire on the margins of the upper body and the lower beak |
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9 Sheath fronts of lower cauline leaves transversely rugose. |
10 Perigynia mostly > 2× as long as wide, widest near the base |
10 Perigynia mostly < 2× as long as wide, widest near middle. |
11 Inflorescence usually branched, at least at the base, usually with > 15 spikes; pistillate scales usually yellow or brown, sometimes with hyaline margins, 3-veined |
11 Inflorescence unbranched or with 1 or 2 short branches at the base, with < 15 spikes; pistillate scales greenish hyaline, 1-veined |
9 Sheath fronts of lower cauline leaves smooth (or very weakly and indistinctly transversely rugose). |
18 Fronts of leaf sheaths dotted red, brown, or yellow. |
19 Perigynia widest near the base; culms usually > 1 mm wide |
19 Perigynia widest near the middle; culms usually < 1 mm wide. |
20 Plants densely cespitose, with short rhizomes; pistillate scales acute to acuminate |
20 Plants loosely cespitose, sometimes with long rhizomes; pistillate scales (at least the upper) obtuse |
18 Fronts of leaf sheaths not dotted red, brown, or yellow. |
21 Perigynium beak < 0.25 mm long, the margins entire |
21 Perigynium beak > 0.25 mm long, the margins often serrulate. |
22 Upper leaves of culms with front of sheaths green-veined, not differentiated from the rest of the sheath |
22 Upper leaves of culms with front of sheaths with at least a narrow hyaline or whitish- hyaline band extending at least ½ the length of the sheath. |
23 Perigynia with flat, winglike margins > 0.1 mm wide; plants long- rhizomatous, not cespitose, sometimes forming large colonies |
23 Perigynia without a flat margin, or with a flat margin < 0.1 mm wide; plants short- rhizomatous or inconspicuously rhizomatous, cespitose or not, sometimes forming large colonies. |
24 Plants colonial from long rhizomes or stoloniferous ( proliferating from last year’s decumbent sterile culms) |
25 Plants long stoloniferous, proliferating from last year’s decumbent sterile culms |
25 Plants rhizomatous from creeping rhizomes 1.8-3.5 mm in diameter |
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26 Spikes not consistently androgynous, the terminal either entirely staminate or pistillate, the lateral spikes irregularly pistillate, or staminate, or mixed |
26 Spikes consistently androgynous, occasionally some of the lateral spikes entirely pistillate. |
27 Perigynium widest near the base, tapering from base to beak |
27 Perigynium widest above the base, often abruptly beaked |
1 Apex of perigynium beak with 2 teeth at least (0.4-) 0.5 mm long. |
2 Perigynia with 2 distinct marginal veins, otherwise veinless or only very faintly veined; leaves not septate- nodulose |
2 Perigynia with 5+ distinct veins; at least proximal leaves septate- nodulose, rarely not. |
3 Perigynia with serrulate wing on margins; spikes usually 20+, sessile, pistillate or androgynous and similar in appearance, forming a dense, ovoid or oblong head, rarely with proximal spike separated |
3 Perigynia without wing on margins; spikes not more than 10, usually at least proximal shortly pedunculate, sometimes subsessile, distal and proximal spikes usually dissimilar in appearance, usually not crowded into a dense head. |
4 Pistillate scales obtuse to acuminate, awnless or at most with a rough apiculus. |
5 Staminate spike usually 1; perigynia 15-20-veined, each 10-20 mm long |
5 Staminate spikes usually 1-3+; perigynia 6-15 (-22)-veined, each 4-10 (-12.5) mm. |
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7 Perigynia narrowly ovate to subglobose, 2-2.5× as long as wide |
7 Perigynia elliptic to ovate, 3-4.5× as long as wide |
4 Pistillate scales, at least some, with a scabrous awn. |
8 Perigynia (9-) 10+ mm long. |
9 Pistillate spikes cylindric, much longer than wide; staminate spikes (1-) 2-6 |
9 Pistillate spikes globose, ovoid, or cylindric, about as long as wide; staminate spikes usually 1 |
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10 Upper pistillate scales with awn > ½ as long as the body |
10 Upper pistillate scales acute to short-awned, awn < ½ as long as the body. |
11 Beak of perigynia with teeth 1.1-3 mm long |
11 Beak of perigynia with teeth often < 1 mm long. |
12 Staminate spikes 1 (-4); perigynium beak > 1.7 mm long |
12 Staminate spikes 1-6; perigynium beak often < 1.7 mm long. |
13 Perigynia veined only at base; widest leaves < 4 mm wide |
13 Perigynium veined to tip of body and often into beak; widest leaves mostly > 4 mm wide. |
14 Pistillate scales with margins serrulate distally; awn, when present, rough. |
15 Perigynia 3.1-4.8 × 0.9-1.5 (-1.8) mm; staminate spikes 1-2 |
15 Perigynia 2.5-8 × 1.2-3.5 mm; staminate spikes usually 3-7 |
14 Pistillate scales with margins entire; awn, when present, usually smooth. |
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16 Perigynia 14-25-veined. |
17 Perigynia narrowly ovate to subglobose, 2-2.5× as long as wide |
17 Perigynia elliptic to ovate, 3-4.5× as long as wide |
1 Apex of perigynium beak entire, emarginate, or with 2 teeth < 0.5 mm long. |
18 Perigynia minutely papillose, at least distally (at 20× magnification). |
19 Some roots with yellow-brown felty covering |
19 Roots brown or black, without yellow-brown felty covering, rarely with white felty covering. |
20 Leaf blades and/or sheaths pubescent, at least at junction of blade and sheath |
20 Leaf blades and sheaths glabrous. |
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22 Lower pistillate scales with awn 1.2-3.5 mm long; staminate scales awned |
18 Perigynia not papillose, essentially smooth. |
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24 Perigynia with distinct beak 0.5-4 mm long. |
25 Larger spikes usually with > 50 perigynia; achenes 2-3 mm long |
25 Larger spikes with < 40 perigynia; achenes 1-2 mm long |
24 Perigynia beakless or with beak < 0.5 mm long. |
26 Adaxial side of leaves with 2 marginal veins more prominent than midvein; young leaves M-shaped in cross section. |
27 Perigynia ovoid, usually > 1.5× as long as wide; apex tapered to beak; sheaths of proximal leaves not septate- nodulose |
27 Perigynia subcircular, < 1.2× as long as wide; apex rounded, abruptly beaked; sheaths of proximal leaves septate- nodulose |
26 Adaxial side of leaves without 2 marginal veins more prominent than midvein; young leaves V-shaped or rounded in cross section. |
28 Leaf blades and/or sheaths pubescent, at least at junction of blade and sheath |
28 Leaf blades and sheaths glabrous. |
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29 Perigynia ascending, spreading at about right angles, or reflexed when mature |
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30 Leaves and/or sheaths pubescent, at least at junction of blade and sheath. |
31 Larger leaves 8-23 mm wide, only the sheaths pubescent |
31 Leaves < 8 mm wide, blades and usually also the sheaths pubescent. |
32 Perigynium beak 0.5-3 mm long, often > 1 mm long, about 1/2 the length of the body; proximal pistillate scales awned |
32 Perigynium beak absent or not more than 0.5 (-0.7) mm long, not > 1/4 the length of the body; proximal pistillate scales acute, acuminate or cuspidate. |
30 Leaves and sheaths usually glabrous, rarely papillose. |
33 Style persistent on achene in fruit; larger leaves and sheaths usually at least sparsely septate- nodulose, rarely not. |
34 Perigynia (9-) 10+ mm long; staminate spike usually 1 |
34 Perigynia < 10 mm long; staminate spikes 1-5 (-7). |
35 Pistillate scales with margins serrulate distally, apex usually rough-awned. |
36 Distal pistillate scales with apex acute to short-awned, awn < 1/2 as long as the body |
36 Distal pistillate scales with apex long-awned, awn > 1/2 as long as the body |
35 Pistillate scales with margins entire, apex awnless or with short, smooth awn. |
37 Perigynia not inflated, thick walled, brownish, dull |
37 Perigynia slightly to strongly inflated, thin walled, yellowish to purplish, shiny |
33 Style deciduous; larger leaves and sheaths sometimes septate- nodulose, more often not. |
38 Leaf blades, at least widest, M-shaped in cross section when young, adaxial surface with 2 marginal veins more prominent than midvein. |
39 Widest leaf blades 8-23 mm wide, septate- nodulose |
39 Widest leaf blades < 6 mm wide, not septate- nodulose. |
40 Pistillate scales awned, longest awn > 0.5 mm long |
40 Pistillate scales obtuse to acuminate or short-awned, awn < 0.2 mm long |
38 Leaf blades V-shaped in cross section when young, adaxial surface without 2 marginal veins more prominent than midvein. |
41 Proximal perigynia in each spike spreading at right angles or reflexed at maturity; leaf blades and sheaths sparsely septate- nodulose |
41 Proximal perigynia in each spike ascending or spreading- ascending; leaf blades and sheaths not septate- nodulose. |
42 Plant base brown or blackish, without trace of red or purple |
42 Plant base red or purple tinged, sometimes only sparsely so. |
43 Perigynia distinctly veined on faces; pistillate scales brown or black |
43 Perigynia veinless or with veins only proximally; pistillate scales white- hyaline or red-brown |
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. |
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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 |
