PLATE XVIT. 



FIGS. PAGE 



1-4. Closterium Ehrenbergii Menegh. 1 and 2, x 



220; 3, x 120; 4, zygospore, x 220 . 143 



5-6. Cl. Malinvernianum ~De Not. 5, x 220 ; G, x 



520 . . . . . 145 



7-8. Cl. decorum Breb. x 200 (after Brebisson) . IS I- 

 9-10. C/. lanceolatnmKutz. 9, x 300; 10, x 520 . 149 

 11. CL Innceolatum var. parvum West & G. S. 



West, x 520. 150 



