Jones: Flora of Illinois, 23. Cyperaceae 81 



ll.Perigynia 2.5-3.5 mm. long, obovoid, squarrose-spreading, 



shorter than the glumes; meadows, s. Ill 



C. bushii Mack. 



10. Perigynia 4-6 mm. long, ellipsoid, ascending, the beak short, 

 bidentulate; glumes awned, hyaline-margined; leaves 3-8 

 mm. wide; roadside ditches and alluvial soil in woods, fre- 

 quent C. davisii Schw. 8C Torr. 



9. Terminal spike staminate. 



12. Perigynia tapering at the base, triangular in cross-section. 

 13. Pistillate glumes mucronate or awned; stems phyllopodic; 

 stolons deep-seated; plants of open marly or sandy soil. 

 14. Pistillate spikes cylindrical, 3-4.5 mm. thick; sandy 



soil C. tetanxa Schk. 



14. Pistillate spikes ellipsoid, 5-8 mm. thick; meadows 



and prairies C meadii Dewey 



13. Pistillate glumes obtuse; pistillate spikes 3-4 mm. thick; 

 stems aphyllopodic; stolons superficial; woodland 



plants C. woodii Dewey 



12. Perigynia rounded at the base, nearly terete in cross-section. 

 15. Pistillate glumes mucronate or awned. 



16. Leaves 5-10 mm. wide; perigynia 2-2.5 mm. long; 



plants cespitose; alluvial soil, n.e. Ill 



C. haleana Olney 



16. Leaves 1.5-3 mm. wide; perigynia 3-3.5 mm. long; 



plants stoloniferous; sandy flats, n.e. 111., rare 



C. crawei Dewey 



15. Pistillate glumes acute; leaves 3-9 mm. wide; perigynia 

 2-3.5 mm. long; moist meadows and woods, common 



C. gramdar'is Muhl. 



6. Mature perigynia faintly impressed-nerved or nerveless; spikes erect 

 or ascending. 

 17. Terminal spike staminate; pistillate glumes mucronate or awned. 

 18. Sheaths and lower blades pubescent; perigynia 2.5 3 mm. 



long; moist ground, rare. "N. 111.," Vasey 



C. pallescens L. 



18. Plants glabrous; perigynia 3.5-5.5 mm. long. 



19. Perigynia 1.5 mm. wide; bract-sheaths with serrulate mar- 

 gins; peduncles of the pistillate spikes scabrous; mead- 

 ows and ditches, not common C. conoidsa Schk. 



19. Perigynia 2-2.5 mm. wide; bract-sheaths and peduncles 



smooth or nearly so. 



20. Pistillate spikes 3-12-flowered; leaves thin, soft, not 



glaucous. 



21. Perigynia 4.5-5.5 mm. long; awn of the pistillate 



glumes minutely serrulate; stems brownish at 



base; leaves 4-8 mm. wide; woods, thickets, and 



meadows, common C. grisea Wahl. 



