PLATE XV. 



FIQS. PAGE 



1-6. Closterlum Dianie Elirenb. 1-3, x 220 ; 4, 



x 200 (after Ralfs); 5, extremity of cell, 



x 830 ; 6, zygospore, x 220 . .130 



7_8._C/. PneudodiansB Roy. 7, x 400 (after Roy) ; 



8, x 400 . . ' . . 132 



9-12. Cl. parndum Nag. 9, x 300 (after Nageli) ; 



10 and 11, x 520; 12, zygospore, x 300 . 133 

 13-14. 01. parvuluiu var. angustumWest & G. S. West. 



x 520 . . . . 134 



15-20. CL Venn* Kiitz. x 520 ; 18-20, zygospores . 137 

 21-22. CL Dianse var. arcuatum (Breb.) Rabenli. x 



220 (after Brebisson) . . .131 



23-25. CL Jenneri Ralfs. 23, x 200 (after Ralfs) ; 



24 and 25, x 520 . . . 134 



26-27. CL Jenneri var. robuntum G. S. West, x 520 . 136 

 28-30. CL inein-vum Breb. 28 and 29, x 520; 30, 



x 200 (after Brebisson) . . .136 



