GEAMINEjE. 



251 



5. CAREX IKTiriKES'CENS. 

 The species of the genus Cai-ex are exceedingly numerous and 

 difficult of study. The one we have selected (Fig. 259) is one of 

 the commonest and at the same time 

 one of the easiest to examine. In this 

 genus the flowers are monceoious, the 

 separate kinds being either borne in 

 different parts of the same spike or 

 in different spikes. The genus is dis- 

 tinguished from all the others of this 

 Order by the fact of the achene being 

 enclosed in a bottle-shaped more or less 

 Fig. 26U. jlijjlated sac, which is made by the 

 union of the edges of two inner bract- 

 lets or scales. To this peculiar sac 

 (Figs. 260 and 261) which encloses the 

 achene the name perigynium is given. 

 The culms are always triangular and 

 the leaves grass-like, usually rough- 

 ened on the margins and on the keel. 

 In the species under examination 

 (which may be found in almost any 

 wet meadow) the culm is some 18 

 Fig. 261. inches high. The staminate spike 

 (only one) is separate from and above the fertile 

 ones, which are 2 or 3 in number, few- (5 to 8) 

 flowered, and quite near together. The perigynia 

 are very much inflated, that is, very much larger 

 than the achene ; they are distinctly marked with 

 many nerves, and taper gradually into a long 2- 

 toothed beak from which J)rotrude the 3 stigmas. 

 The bracts which subtend the spikes are leaf-like, 

 and extend much beyond the top of the culm. 



Obdeb CXI. GRAMIN'E.S:. (Gbass Family.) 

 Herbs somewhat resembling those of the last Order, but the 

 culms are hollow except at the joints, and the sheaths of the 

 leavw are split on the opposite side of the culm from the blade. 



Fig. 259 



