145. Cyi'eraceae 321 



14. Perigynia 2-3.5 mm long; lake shores and river 

 banks, locally in n.c. Ill C. viridula Michx. 



14. Perigynia 5.5-6.5 mm long; open woods, rare; 



Hardin Co., R. H. Mohlenhrock in 1954 



C. dehilis Michx. 



13. Beak of the perigynium 2-2.5 mm long, equalling or 

 exceeding the body. 



15. Pistillate spikes erect, sessile; perigynia spreading 



or reflexed, 2-3 times as long as the glumes; 

 wet meadows in n.e. Ill C. cryptolepis Mack. 



15. Pistillate spikes pendulous on slender peduncles; 

 perigynia spreading-ascending, slightly longer 

 than the glumes; beak smooth; alluvial soil 

 in the northern half of the state. [C longi- 



rostris sensu Torr., non Krock.] 



C. sprcngelii Dewey 



1. Staminate spikes two or more; perigynia ovoid to ellipsoid, often 

 more or less inflated. 



16. Teeth of the perigynium short, usually not more than 0.5 mm 

 long. 



17. Perigynia ascending, fusiform or narrowly ellipsoid, short- 

 beaked, the beak not more than 1 mm long. 

 18. Mature perigynia strongly-nerved; stems aphyllopodic, 

 purplish and filamentose at base; swamps and 

 ditches, local C. lacustris Willd. 



18. Mature perigynia finely impressed-nerved ; stems phyl- 

 lopodic, light brownish at base; ditches, and wet 



ground in woods, local C. hyalinolepis Steud. 



17. Perigynia spreading or reflexed, ovoid-lanceoloid, inflated, 

 papery, strongly nerved, the beak 2-3 mm long; swampy 



ground, local C. retrorsa Schw. 



16. Teeth of the perigynium 0.5-2 mm long. 



19. Perigynium 5-6 mm wide, 7-10 mm long, the teeth 0.5-1 

 mm long; wet ground in woods; Cook, Lake, Winne- 

 bago, and Hancock counties C. tuckermani Dewey 



19. Perigynium 2-3 mm wide. 



20. Teeth 1-3 mm long; perigynium dull; style straight. 

 21. Sheaths and blades pubescent; prairie sloughs, rare; 



Winnebago Co., E. W. Fell ....C. atherodes Spreng. 

 21. Sheaths and blades glabrous; marshy ground, local- 

 ly in the northern half of the state 



C. laeviconica Dewey 



20. Teeth 0.5-1 mm long; perigynia glossy; style flexuous or 

 abruptly bent. 



