PLATE LIV. 



FIGS. PAGE 



1-3. Micrasterias Americana (Ehrenb.) Ealfs. x 520. 



2, vertical view ; 3, side view of semicell . 117 

 4. M. Americana var. recta Wolle. x 400 . 119 



5-6. M. Americana var. Lewisiana West, x 400 . 120 

 7-8. M. MahabulesJiwarensis Hobson var. Wallichii 



(G-run.) West & G. S. West. 7, x 200; 



8, x 430 . . . 122 



