ï~~2000
THE MICHIGAN BOTANIST
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line, fragile and often curled, the midrib not extending into the very
tip........................................C. m issouriensis
5. Larger perigynia (2.3-) 2.5-5.5 mm long, with beaks 0.85-2.3
mm long; pistillate scales with the apex firm, greenish to reddishbrown, straight, the midrib extending to the very tip.
6. Perigynium bodies clearly obovate, often with conspicuous
"shoulders," abruptly contracted into the beak; broadest
leaves 2.5-6 mm wide................................ C. alata
6. Perigynium bodies elliptical, circular, or weakly obovate,
gradually tapered to gently contracted into the beak; broadest
leaves 1.5-3 (-3.7) mm wide.
7. Perigynium bodies cuneately tapering to the base, the
base therefore subacute and the body Â~ diamond shaped;
inflorescences Â~ compact, stiffly erect, with 3-5 spikes................................................. C. suberecta
7. Perigynium bodies convexly tapered to the base, the base
therefore rounded and the body elliptical, circular or
weakly obovate; inflorescences Â~ compact to elongate
and nodding, with 3-9 spikes.
9. Pistillate and staminate scales with white-hyaline to
pale yellowish margins; perigynia greenish to straw
colored or pale brown, (2.3-) 2.5-4 (-4.2) mm long,
with 0-4 often indistinct nerves on the inner face................................... C. festucacea
9. Pistillate and staminate scales with reddish-brown
margins; perigynia reddish-brown, (3.8-) 4-5.5 mm
long, usually with 5 or more conspicuous nerves on
the inner face...................... C. straminea
3. Pistillate scales obtuse or merely acute
10. Perigynia 2 mm wide or less
11. Leaf sheaths loose and expanded near the summit, uniformly pale
or greenish, sharp-edged or bearing narrow wings continuous
with the midrib and/or edges of the leaf blade; widest blades 3-7
mm wide; perigynia often thin and scale-like, the wings often
conspicuously narrowed (even indented) near the middle of the
body to form a cuneate base; vegetative shoots with leaves
spreading and spaced along distal 1/2 of the shoot
12. Perigynia stiffly spreading or recurved, the spikes more or
less globose; pistillate scales 1.6-2.3 mm long, usually hidden between perigynia; summit of leaf sheaths and/or ligules
often rust-tinged........................... C. cristatella
12. Perigynia loosely spreading, ascending, or appressed, the
spikes subglobose to ovoid-oblong; pistillate scales 2-3 mm
long, evident in the spikes; summit of leaf sheaths and ligules
not colored
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