52 



CYPEEACEAE. 



Culms exceeding the leaves : lowest bract leaflet-like, 

 U.5-3 mm. wide : pistillate spikes lineai--cylindric : 

 perigj'nia elliptic. 

 Perigynia glabrous at least at maturity. 



Perigynia much flattened, rounded at the apex, lightly 



nerved. 

 Perigynia swollen, nearly orbicular in cross-section, 

 pointed at the apex, coarsely nerved. 

 Perigynia 2 mm. long, brownish-green : scales not 



rough-cuspidate. 

 Perigynia longer, green : scales rough-cuspidate. 



A single species In our range. 



XX. Anomalae. 



XXI. RiGIDAE. 



Culms very strongly tufted, slender, very rough above : 



perigynium-beak very short, not twisted. 

 Culms tufted and short-stoloniferous, stout at the base, 



smooth above : perigynium-beak prominent, twisted when 



dry. 



XXII. Ceyptocarpae. 



Sheaths rough-hispid : lower pistillate scales tapering into 



awn. 

 Sheaths smooth : lower pistillate scales abruptly contracted 



into awn. 



A single species in our range. 



A single species in our range. 



XXIII. Atratae. 



XXIV. Shortianae. 



XXV. HiRTAE. 



Perigynium-beak much shorter than body, the teeth 1 mm. 

 long or less. 

 Perigynia glabrous. 

 Perigynia densely pubescent. 



Perigynium-beak with hyaline orifice at length some- 

 what bidentate : staminate spike usually one, ses- 

 sile or short-stalked. 

 Perigynium-beak with non-hyaline strongly bidentate 

 orifice : staminate spike long-stalked. 

 Leaf-blades flat, more than 2 mm. wide. 

 Leaf-blades involute, 2 mm. wide or less. 

 Perigynium-beak, including teeth, nearly as long as the 

 body, the teeth 1.5 mm. long or more. 



XXVI. FOLLICULATAE. 



A single species in our range. 



XXVII. Physocarpae. 



Pistillate scales (except rarely the lowest) not rough- 

 awned. 



Beak of perigynium smooth. 



Beak of perigynium rough. 

 Pistillate scales rough-awned. 



53. C. virescens. 



54. C. complanata. 



55. C. caroliniana. 

 50. C. Busfiii. 



57. C. scabrata. 



58. C. stricta. 



59. C. torta. 



60. C. gynandra. 



61. C. crinita. 



62. C. Buxhaumii. 



63. C. Shortiana. 



64. C. lacustris. 



65. C. vestita. 



66. C. lanuginosa. 



67. C. lasiocarpa. 



68. O. trichocarpa. 



69. C. folliculata. 



70. O. monile. 



71. G. huUata. 

 T2. O. lurida. 



XXVIII. Pseudo-Cypereae. , 



Perigynia suborbicular in cross-section, more or less in- 

 flated. 



Perigynia obtusely triangular, scarcely inflated, closely 

 enveloping achene. 



XXIX. Squarrosae. 



Scales exceeding perigynia : terminal spike small, normally 

 staminate. 



Scales much shorter than perigynia : terminal spike stami- 

 nate at base, pistillate above. 



73. O. hystricina. 



74. C. comosa. 



75. G. Frankii. 



76. C. squarrosa. 



