OP NAIAS GRAMINEAj VAR. DEHLEI. 



53 



all its stages of growth, and, from all that I have seen, it 

 keeps pace uniformly with the growth of the membrane of 

 the anther. 



The anthers of this genus, according to Dr. Magnus, are 

 axis-growths which, when ripening, are pushed through 

 the perianth, rupturing that membrane somewhat irregu- 

 larly, and they finally dehisce at their apex. That the 

 anthers of the Reddish plant dehisce at the apex there is 

 no doubt, but I have seen no trace of the rupturing of the 

 outer perianth-membrane through the emergence of the 

 anther proper ; on the contrary, the summit of the flower 

 presents a regularity of parts for which Dr. Magnus's 

 observations did not prepare me. The rupturing of the 

 perianth in N. major is shown in figs. 22 & 28 on 

 Plate VI. 



Fig. 74. 



Fig- 75- 



Fig. 76. 



In an early stage the antheriferous flower of N. graminea 

 has its outer membrane prolonged into two erect rounded 

 ears, which are continued down the sides as keels or ridges 

 (figs. 67 & 75). The young pollen at this stage is distinctly 

 seen through the membranes of the flower and of the 

 anther (fig. 76). The anther then becomes more elongate 

 by its upward growth ; a slight groove makes its appear- 

 ance longitudinally, corresponding with the principal 

 dissepiment of the anther (fig. 68) ; the upright ears and 

 the keels lose their prominence, and the separate pollen- 

 grains are not so distinguishable (fig. 77). Finally, the 

 mature quadrilocular anther is an ovoid cylindrical body 



