CYPERACEAE. 



69 



Stems equalling or exceeding the leaves; lowest 

 bract not colored nor auricled at base; perigynia 

 3-8. C. rossii. 



Plant stoloniferous; none of the flowering stems short 



and hidden among the leaves; spikes dark. 



Perigynia obovoid, whitish. C. vespertina. 



Perigynia ellipsoid, brown at base. C. verecunda. 



Perigynia glabrous or merely granular-roughened. 



Beak of membranaceous somewhat inflated perigynium 

 deeply bidentate, the long teeth sharp and rigid; 

 leaves conspicuously nodulose. 



Pistillate spikes drooping. C. comosa. 



Pistillate spikes erect or ascending. 



Perigynia shiny, ascending, much inflated, 10 mm. 



long. C. exsiccata. 



Perigynia not shiny, spreading, not much inflated, 



4-8 mm. long. C. utricidata. 



Beak of perigynium wanting or if present entire or merely 

 emarginate, or if bidentate the teeth short; leaves 

 not conspicuously nodulose. 

 Stigmas 3 and akenes 3-angled. 



Spikes narrowly cylindrical, 610 cm. long; peri- 

 gynia granular, spreading; leaves 1-2 cm. broad. C. amplifolia. 

 Spikes not so long and slender; perigynia smooth; 



leaves not so broad. 



Perigynia spreading, the beak bidentate. C. oederi. 



Perigynia not spreading, the beak entire or 



emarginate, scarcely bidentate. 

 Terminal spike pistillate above, staminate 



below. 

 Spikes erect; scales obtusish; perigynia 



inflated, 3 mm. long. C. accedens. 



Spikes more or less drooping; scales 

 sharp-pointed; perigynium not 

 inflated. 

 Scales acute or acuminate; perigynia 



nerveless, 3.5 mm. long. C. atrata. 



Scales mucronate; perigynia nerved, 



5 mm. long. C. mertensii. 



Terminal spike wholly staminate. 



Pistillate spikes slender peduncled, 



usually drooping. 

 Scales acute or cuspidate, about as 



long as the perigynia. 

 Staminate spike linear; scales 

 pale; leaves 1-3 mm. broad; 

 rootstock creeping. C. limosa. 



Staminate spike oblong-cylindric; 

 scales dark; leaves 4-8 mm. 

 broad, tufted. C. spectabilis. 



Scales cuspidate or aristate, much 



longer than the perigynia. 

 Perigynia broadly ovate to orbi- 

 cular. C. paupcrciilu. 

 Perigynia elliptic-lanceolate. C. macrocliaeta. 

 Pistillate spikes erect. 



Scales brown; leaves 2-5 mm. broad. C. ablatn. 

 Scales pale. 



