SEDGE FAMILY. 85 



Spikelets unisexual or rarely androgynous; Staminate flowers forming 1 or more terminal 

 linear or club-shaped spikelets, which are occasionally sparingly androgynous; pis- 

 tillate (lowers usually in distinct and simple mostly pedicellate spikelets; cross-section 

 of the perigynium circular, obtusely angled or prominently trigonous in outline; style 

 mostly 3-parted; achene mostly trigonous or triquetrous. Sub-genus Eu-carex Coss. 

 Perigynium large, tapering into a beak as long as or longer than the body, papery in 

 texture, more or less inflated, smooth, nerved, straw-colored or occasionally purple 

 at maturity; spikelets few to many, distinct, compactly flowered; stigmas 3. 

 Perigynium much inflated, usually prominently few-nerved, beaked, conspicuously 

 short-tOOthed; staminate spikelets commonly 2 or more; pistillate usually long 



and densely cylindrical: plants mostly large and stout 1. C. vesicaria. 



Perigynium less in Hated, more conspicuously nerved or even costate; teeth more or 

 less setaceous or aristate; bractlet usually aristate; spikelets mostly nodding, 



comose in appearance 2. C. pseudocyperus. 



Perigynium small, nearly or entirely beakless and mostly entire mouthed, thinner in 



texture; mostly paludose species with colored spikelets; often growing in dense tufts 



or tussocks. 



Spikelets short and erect, very closely flowered, the terminal strictly staminate; 



bracts with purple or black auricles at base; stigmas 2 or 3; mostly stiff and 



rigid species. 



Stigmas 3 3. C. bifida. 



Stigmas 2 4. C. nudata. 



Spikelets long and large, green or light-colored; stigmas 2; species larger, distinguished 

 mainly by habit; mostly paludose. 



Stems clothed with dead sheaths below; spikelets mostly long pedicellate 



5. C. obnupta. 



Stems spongy at base; spikelets mostly sessile 6. C. aquatilis. 



Spikelets large, cernuous or drooping, mostly dark-colored; stigmas 2; bractlets very 



long and conspicuous; plants large 7. C. sitclicnsis. 



Perigynium mostly short and rounded; beak straight and usually 2-fid, firm or hard 

 in texture, not inflated, hairy or scabrous; staminate spikelet 1; pistillate spikelets 

 1 in. or less long, usually globular or short-oblong, more or less sessile and ap- 

 proximate, or the longer ones radical; bracts sheathless, short or obsolete; stigmas 

 rarely 2; low species of dry ground, with leaves all radical. 

 Spikelets 2 to several, the lowest occasionally long-pedicellate and radical; perigynium 

 abruptly rounded above, contracted above and below, bearing a more or less 



prominent rib on each side 8. C. globosa. 



Spikelets androgynous (rarely dioecious or some of the spikelets unisexual) ; staminate 

 flowers usually borne at the base or apex of the pistillate spikelets, rarely the 

 staminate and pistillate flowers irregularly situated; pistillate flowers mostly in short 

 and sessile spikelets (in some cases the spikelets single) wdiich are commonly aggre- 

 gated into heads or even panicled; cross-section of the perigynium plano-convex 

 in outline; styles 2; achene lenticular; the spikelets, especially the uppermost, usually 

 have contracted bases when the staminate flowers are borne below the pistillate ones, 

 and empty scales at the top when the staminate flowers are borne above. — Sub-genus 

 Yigneae Koch. 

 Fluzccrs often dioecious or nearly so, or the staminate and pistillate flowers irregularly 

 situated, or some of the spikelets occasionally wholly staminate or pistillate. 

 Inflorescence a simple or nearly simple head; perigynium ovate, stipitate, concealed 



by the bractlet, at length nearly black 9. C. marcida. 



Flozccrs monoecious; SDikelets regularly androgynous, the staminate flowers uniformly 

 borne at the top. 

 Spikelets yellow or tawny when mature, short, rarely longer than broad; perigynium 

 mostly small and short and nearly nerveless, or in some species becoming nearly 

 lanceolate and more or less prominently nerved, firm in texture. 



Inflorescence a simple or nearly simple head 10. C. brongniartii. 



Spikelets green or nearly so when mature, aggregated or scattered, never in compound 

 heads; perigynium mostly short-ovate, in most cases not conspicuously nerved. 



Plants slender; spikelets more or less scattered 11. C. muricata. 



Fluzccrs monoecious; spikelets regularly androgynous, the staminate flowers uniformly 



borne at the base. 



Inflorescence silvery green or sometimes tawny when mature; spikelets mostly small, 



distinct; perigynium not wing-margined nor conspicuously broadened, mostly 



nearly flat on the inner surface. 



Perigynium ovate, sharp-margined, firm, often thickened at the base, spreading, 



in open, and at maturity stellate, spikelets 12. C. echinata. 



Perigynium ovate-lanceolate or nearly linear, mostly in loose spikelets 



13. C. deweyana. 



