PLATE XLIV. 



PIGS. PAGE 



1-2. Micrasterias papillifera Breb. x 400 . .91 



3. M. papillifera forma major. x 220 . .92 



4-5. M. papillifera var. glabra Nordst. 4, x 520 ; 



5, x 400 . . .93 



6. M. papillifera var. varvicensis Turn, x 250 (after 



Turner) . . . .93 



7. M. papillifera. Zygospore, x 200 (after Ralfs) 91 



