PLATE CXVII. 



FIGS. PAGE 



1. ArtJirodesmus subulatus Kiitz. Z)'gospore, x 



about 500 (after Borgesen) . . 109 



2-3. A. siibulatus var. mbaequalis W. & G. S. West. 



x 520 . . . . 110 



4-5. A. siibulatus forma americana (Turn.) W. & 

 G. S. West. 4, x 500 (after Turner) ; 5, x 

 400 . . . . . 110 



6-10. A odocornis Elirenb. 6, 7, and 9, x 520; 8, 



x 400; 10, zygospore, x 520 . .Ill 



11-13. A. bifid-its Breb. 11, x 450 (after Brebissoii) ; 



12 and 13, x 400 . . 113 



14. A. bifidus var. truncatus West. x 520 . 114 



15. A. bifidus var. truncatus forma succisa W. & 



G. S. West, x 520 . . .115 



16. A. bifidus var. latidivergens West. x 400 . 11.5 



17. A. trispinatus W. & G/S. West. x 520 . 115 



18-19. A. temdssimus Arch. x 520 . .116 



20. A. tenuissimus forma longispina W. & G. S. 



West, x 400. . . .117 



21. A. octocornis Ehreub. forma impar (Jacobs), x 



about 400 (after Jacobsen) . .113 



22. A. pliimus Turn. var. hebridarum W. & G. S. 



West, x 460. . . 105 



23-24. Xantliid'mm aculeatum Ehrenb. var. basiden- 

 tatum (Borges.) W. & G. S. West. 23, x 

 400 (after Lutkemiiller) ; 24, x about 360 

 (after Borgesen) . . .80 



