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.
6 Perigynia 6-14 (-15)-veined
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.
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 1-6;
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.
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
22 Lower
pistillate scales with
awn 1.2-3.5 mm long;
staminate scales awned
18 Perigynia not
papillose , essentially smooth.
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
29 Perigynia ascending , spreading at about right angles, or
reflexed when mature
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 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
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).
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
13 Culms with some red or purple at
base .
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
19 Bracts without
blades .
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 .
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
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.
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 .
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.
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 .
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 brown at
base , without trace of red or purple;
achenes with
style deciduous