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 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.
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
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.
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 .
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
28 Leaf blades and sheaths
glabrous .
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 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