CYPERACEAE 



153 



Spikelets subterete, few-flowered. 



Spikelets 12-25 mm. long, loosely spicate, 



the lower reflexed. 

 Spikelets 3-10 mm. long, densely capitate 

 or spicate. 

 Spikelets all reflexed; culms rough. 

 Spikelets spreading or the lower re- 

 flexed; culms smooth. 

 Heads oblong or cylindric. 



Spikelets 4-10 mm. long, at 

 least the lower re- 

 flexed. 

 Head oblong or short- 

 cylindric; lower 

 spikelets reflexed. 

 Head obovoid; all but 

 the upper spikelets 

 reflexed. 

 Spikelets 3-4 mm. long, the 

 lower spreading. 

 Heads globose. 

 Achene oblong or obovoid, about tiwce as long as 

 thick. 

 Rachis wingless or very narrowly winged. 

 Heads globose. 

 Heads oblong. 

 Rachis-wings membranous, broad. 



Scales firm, not appressed ; spikelets loosely 



capitate. 

 Scales thin, closely appressed; spikelets 

 densely capitate. 



19. C. refractus. 



20. C. retrofractus. 



21. C. lancastriensis. 



22. C. hystricinus. 



23. C. Torreyi. 



24. C. ovularis. 



25. C. filiculmis. 



26. C. cayennensis. 



27. C. Grayi. 



28. C. elobulosus. 



C. flavescens L. In marshy ground: N. Y. to Mich., Fla., 

 Mex. and Costa Rica. Also in the Old World. 



N. Y. In Bronx and Westchester counties, and on western L. I. 



and on S. I., unknown elsewhere. 

 N. J. Rare in Warren, Hunterdon, and Morris counties, increasing 



southward. 

 Pa. Northampton, Bucks, Philadelphia, Delaware and Chester 



counties. 



Tertiary, common: Cretaceous, common: Older Formations, rare 

 and scattered. 138-220 days. Sea level-1,080 ft. 



C. diandrus Torrey. In marshy places: N. B. to Minn., 

 S. Car., and Kan. 



Throughout the range except the pine-barrens, there not re- 

 corded; rare at Cape May. 



