44 



MR. C. BAILEY ON THE STRUCTURE ETC. 



loosely aggregated (see fig. 58)^ so that there is no well- 

 defined series of marginal cells as in the lamina. The 

 basal cells which support the spines have their longest 

 diameter in the direction of the spine. 



Fig. 58. 



Kg- 59. 



In A^. flexilis (fig. 59) the cells are more loosely aggre- 

 gated also, bnt the line of marginal cells, though not so 

 well defined as in the lamina, is more clearly apparent 

 than it is in N. graminea. The cells of the sheath, as well 

 as the marginal cells of the lamina, of N. flexilis are larger 

 and longer than they are in N. graminea ; but the two 

 species maybe distinguished by the length of the imbedded 

 portion of the spine, which, in N. flexilis, is less, and in 

 N. graminea is more, than one third of its free length. 

 The leaf-cells of N. flexilis generally are larger than those 



