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Stigmas 2;
achenes lenticular. NOT [Stigmas 3; achenes three-sided,
occasionally terete, though their shape may be concealed by flattened
perigynia.] |
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Spikes 2
or more per culm, terminal and lateral; spike bracts present on lateral
spikes; lowest spike bracts usually evident, often conspicuous, even in
compact heads composed of densely bunched and indistinguishable spikes
(except in C. maritima, C. chordorrhiza and C.
microptera). NOT [Spikes 1 per culm, terminal; spike bracts
absent] |
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Individual
spikes distinguishable in an open inflorescence, or indistinguishable in
a compact head; spikes in any one inflorescence alike in appearance due
to their similar composition (i.e. all are gynecandrous, androgynous,
pistillate or staminate), sessile. NOT [Individual spikes
distinguishable in an open inflorescence (densely bunched in C.
bicolor); spikes in any one inflorescence either markedly different
in appearance (with terminal spike staminate and lateral spikes
pistillate), or subtly different in appearance (with terminal spike
gynecandrous and lateral spikes pistillate), sessile or stalked.] |
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Culms
loosely to densely cespitose (occasionally mat-forming rather than in
discrete clumps); rhizomes, if present, usually short with culms arising
close together along them. NOT [Culms single, or a few together,
well-spaced along conspicuous rhizomes or stolons.] |
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Spikes
gynecandrous, (terminal spikes may be staminate in SK material of C.
mackenziei; pistillate or staminate spikes occur in Sect. Stellulatae,
a group distinguished by spongy tissue filling lower one-third to
one-half of the perigynium); if heads have indistinguishable spikes, the
heads are usually +/- as wide as they are long and usually widest in
middle or toward base. NOT [Spikes androgynous, (lateral spikes
occasionally pistillate in C. prairea); if heads have
indistinguishable spikes, the heads are usually oblong to elongate in
shape.] |
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Lower 3 or
4 spike bracts usually scale-like or bristle-like; if lowest is long and
leaf-like, then it is shorter than half the culm length or it appears to
be an extension of the culm to which inflorescence is attached laterally
(as in C. athrostachya); perigynia various. NOT [Lower 3 or
4 spike bracts long, pale-green and leaf-like; lowest bract 5-15 (20) cm
long, usually half to fully as long as culm below inflorescence;
perigynia 5 mm long or longer, narrowly lanceolate.] |
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Perigynium
distinctly wingless though margins may be thickened as rounded or raised
nerves; mature achene filling width of perigynium body; perigynium base
or wall thickened by spongy tissue or cells; beak present or absent. NOT
[Perigynium margins flattened as a narrow or wide wing for all or part
of perigynium length (wing reduced to raised thickened nerve along body
in C. adusta); mature achene narrower than perigynium body; beak
present (though may be ill-defined); neither perigynium base nor
perigynium wall thickened with spongy tissue.] |
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Perigynium
wall thickened by spongy cells toward base (usually only visible after
cutting perigynium in longitudinal section), surface puncticulate giving
it a sparkly, beaded look under magnification. NOT [Bottom
one-third to one-half of perigynium filled with spongy tissue below
achene; surface not punctate or puncticulate (conspicuously or minutely
beset with tiny pits).] |
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Beak
reduced to a nubbin too short to measure; perigynia muted green with
scales translucent to whitish giving the inflorescence a pale,
milky-green cast; spikes nearly round to short oblong; perigynia 3-10
(15 fna) per spike. NOT [Beak measurable, 0.25-1.0 mm long;
perigynia a brighter green with scales often tinged with shades of brown
(often colorless in C. canescens); spike shape variable; perigynia 1-20
per spike.] |
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Spikes
2-5, remote to separate (occasionally overlapping at tip of culm);
perigynia strongly many-nerved; NOT [Spikes 2-4, densely overlapping at
tip of culm; perigynia faintly few-nerved] |