CYPERACEAE 



47 



III. 



Inflorescence usually \\' or more long, the 



clusters compound. 



Beak of the perigynium longer than the body. 

 Beak 1-2 times length of body. 

 Beak 3-4 times length of body. 

 Beak of perigynium shorter than the body. 

 Perigynium and beak 2 X/ long. 

 Perigynium and beak \\" or less long. 

 Scales acute to acuminate. 

 Leaves exceeding stem. 

 Stem exceeding leaves. 

 Scales obtusish. 

 Inflorescence usually less than \\' long, the 



clusters rather simple. 

 Clusters strongly separated. 

 Leaves J"-1J" wide. 

 Perigynia radiating. 

 Perigynia reflexed at maturity. 

 Leaves 2 // -4i // wide. 

 Clusters aggregated. 



Heads green when mature. 

 Leaves 2 // -4 // wide. 

 Leaves "-2" wide. 



Head 6 X/ or less long, the clusters hardly 



recognizable. 

 Leaves l"-2" wide. 

 Leave l // or less wide. 

 Head 6 // or more long, the clusters rec- 

 ognizable. 

 Heads yellowish at maturity. 



IV. 



Perigynia widely spreading. 

 Perigynia not widely spreading. 

 Perigynia 2-5 times as long as wide. 

 Spikes narrowly cylindric, 6" -12" long. 

 Spikes globular to short-oblong. 

 Spikes cone-shaped above. 

 Spikes bluntish. 

 Perigynia erect. 

 Perigynia spreading. 



Perigynia less than twice as long as wide. 

 Heads greenish-brown. 

 Perigynia ovate. 

 Perigynia orbicular. 

 Heads silvery-green. 



32. C. stipata. 



33. C- Crus-Corvi. 



31. C. conjuncta. 



35. C. vulpinoidea. 



36. C. xanlhocarpa. 



37. C. SartweUii. 



38. C. rozea. 



39. C. retroflexa. 



40. C. sparyanoides. 



41. C. ccphaloidea. 



42. C. cephalophora. 



43. C. Leavemvorthii. 



44. C 1 . Muhlenbergh. 

 34. C. gravida. 



45. C. slerilia. 



46. C. Muskingumensis. 



48. C. scoparia. 



47. r C. tribuloides. 



49. C. cristatella. 



50. C. straminea. 



51. C. festucacea. 



52. C. Bicknellii. 



1. C. Asa-Grayi Bailey. 2-3 high : leaves many, 3"-4J" wide : 

 pistillate spike's 1-2, V in diameter, perfectly globular, 10-30-flowered : 

 perigynia much-inflated, many-nerved, 6 // -l(y / long. In low, wet woods 

 near Lake City and Sibley. Rare. May-June. 



2. C. lupulina Muhl. 2-4 high: leaves 2 // -4 // wide: pistillate 

 spikes 2-6, oblong-cylindrical, V-2^ long, densely many-flowered, sessile 

 of short-stalked: perigynia 6 x/ -9 /x long, much inflated, many-nerved. 



