52 



CYPEEACEAE. 



Culms exceeding the leaves : lowest bract leaflet-like, 

 0.5-3 mm. wide : pistillate spikes linear-cylindric : 

 perigynia 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. RlGIDAE. 



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. CRYPTOCAEPAE. 



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. ATEATAE. 



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. 



53. C. virescens. 



54. C. complanata. 



55. C. caroliniana. 



56. C. Bushii. 



57. C. scabrata. 



58. C. stricta. 



59. C. torta. 



60. C. gynandra. 



61. C. crinita. 



62. C. Buxbaumii, 



63. C. Shortiana. 



64. G. lacustris. 



65. C. vestita. 



66. C. lanuginosa. 



67. C. lasiocarpa. 



68. C. trichocarpa. 



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. 



69. C. folliculata. 



70. G. monile. 



71. G. bullata. 



72. G. lurida. 



XXVIII. PSEDDO-CYPEREAE. 



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

 flated. 73. G. Tiystricina. 



Perigynia obtusely triangular, scarcely inflated, closely 



enveloping achene. 74. C. comosa. 



XXIX. SQUARROSAE. 



Scales exceeding perigynia : terminal spike small, normally 



staminate. 75. G. FranJcii. 



Scales much shorter than perigynia : terminal spike stami- 

 nate at base, pistillate above. 76. G. squarrosa. 



