  | Stigmas 2; achenes lenticular. NOT
        [Stigmas 3; achenes three-sided, occasionally terete, though their shape
        may be concealed by flattened perigynia.] | 
        | 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] | 
        | 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.] | 
        | 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.] | 
        | 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.] | 
        | 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.] | 
        | 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.  Section Ovales. 
        NOT [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.] | 
        | Spike bracts usually shorter, or a
        bit longer than the inflorescence; if much longer then clearly
        positioned beneath spike and appearing lateral rather than extending
        culm-like beyond inflorescence.  NOT
        [Lowest spike bract distinctly longer than the inflorescence and
        appearing to be an extension of culm with inflorescence attached to one
        side rather than at tip.] | 
        | Perigynia 5.2 mm long or less
        (occasionally to 6 mm); distance from tip of beak to top of achene 3 mm
        at most; inflorescence nodding or erect; species not confined to Cypress
        Hills.  NOT [Perigynia 6-8 mm long (occasionally as short as 5.5
        mm); distance from tip of beak to top of achene 3.2–4.6 mm;
        inflorescence stiffly erect; Cypress Hills only.] | 
        | Spikes distinguishable, or
        indistinguishable in a compact head; perigynia at most 3 times longer
        than wide (C. praticola occasionally narrower but then pistillate
        scales covering perigynia); other features variable. 
        NOT [Spikes distinguishable; perigynia usually 4 times longer
        than wide, 3-4 (4.7) mm long and seldom over 1 mm wide; scales
        distinctly shorter than perigynia; veins absent or faint on both
        surfaces of perigynia.] | 
        | Perigynium body orbicular, abruptly
        contracted into beak, remaining green until turning tan at maturity;
        pistillate scales one-third to two-fifths as wide as perigynia. 
        NOT [Perigynium body narrower, somewhat contracted or tapering into
        beak; scale width and perigynium color variable.]
         |