CYPERACEAE. 



49 



Perigynia and foliage glabrous, or if 

 pubescent the beak of perigyniuui 

 strongly bideutate. 

 Perigynia rougli papillose, conspicuously 



beaked. 

 Perigynia not rough-papillose. 



Achenes lenticular : stigmas two. 

 Scales obtuse to acuminate, not 



long-aristate. 

 Scales broad, long-aristate. 

 Achenes triangular : stigmas three. 

 Perigynia beakless or very short- 

 beaked. 

 Scales dark-tinged. 

 Scales not dark-tinged. 

 Perigynia with strongly bidentate 

 beaks. 

 Perigynia coriaceous, little if any 

 inflated, often pubescent : bracts 

 sheathless. 

 Perigynia membranous or papery, 

 from little to much inflated, 

 never pubescent (rarely his- 

 pidulous). 

 Perigynia lanceolate, many- 

 nerved, tapering to the beak. 

 Perigynia broader, strongly- 

 ribbed, abruptly contracted 

 into the beak. 

 Perigynia less than 10 mm. 

 long. 

 Perigynium-body ovoid or 

 globose, not truncately 

 contracted. 

 Perigynia coarsely rib-. 



bed. 

 Perigynia finely and 

 closely ribbed. 

 Perigynium-body obovoid 

 or obconic, truncately 

 contracted into the 

 prominent beak. 

 Perigynia 10 mm. long or 

 longer. 



XX. Anomalae. 



XXI. RiGIDAE. 



XXII. Cryptocarpab. 



XXIII. Atratae. 



XXIV. Shortianae. 



XXV. HlRTAE. 



XXVI. FOLLICULATAE. 



XXVII. Physocaepae. 

 XXVIII. Psbudo-Cypereae. 



XXIX. Squaeeosae. 



XXX. LUPULINAB. 



I. Muhlenbeegianae. 



Sheaths tight, inconspicuously if at all septate-nodulose. 



Perigynia corky-thickened at the base, usually widely radiating or reflexed at 

 maturity. 



Perigynium-beak smooth : scales acuminate, deciduous : spikes mostly ap- 



proximate. 



Perigynium-beak minutely roughened : scales obtuse 

 or acutish, persistent. 

 Perigynia not corky-thickened at the base, spreading 

 or ascending. 

 Head 15-36 mm. long, the lower spikes distinct. 

 Head 8-20 mm. long, the spikes densely capitate. 

 Sheaths loose and membranous, easily breaking, conspicu- 

 ously septate-nodulose. 



A single species in our range. 



A single species in our range. 



II. Multifloeae. 



III. Paniculatae. 



1. C. retroflexa. 



2. C. rosea. 



G. Mtihleniergii. 

 G. cephalophora. 



5. C. sparganioides. 



6. C. vulpinoidea. 



7. C. prairea. 



IV. Stenoehynchae. 



Opaque part of sheaths conspicuously transversely rugulose. 

 Opaque part of sheaths not transversely rugulose. 



8. G. stipata. 



9. C laevi-vaginata. 



V. Elongatae. 



Perigynia 4-5.5 mm. long, ascending or appressed, the 

 body not margined. 



Lancaster County Flora 4. 



10. G. bromoides. 



