PLATE CXXXII. 



FIGS. PAGE 



1-4. Staurastrum pterosporum Lund. 1 and 2, x 500 ; 

 3, zygospore, X 400 (after Lundell) ; 4, zygo- 

 spore of biradiate form, X 600 (from a drawing 

 by Dr. J. Lutkemiiller) . . .14 



5-8. St.'O'Mearii Arch. 5 and 6, X ? (after Archer) ; 



7 and 8, X 500 . . . .13 



9. $. O'Mearii var. minutum West. X 500 . 14 



10-11. $. aristiferum Ralfs. X 500 . . 22 



12. $. aristiferum var. protuberans W. & G. S. W. 



X 520 . . . . 23 



13-15.$. cuspidattim Breb. 13* and 14*, x 510 ; 15*, 



zygospore, X 510 . . .23 



16-17. $. cuspidatum var. divergens Nordst. 16, X 400 ; 



17, zygospore, X 400 . . .25 



18-19.$. Gitspidatum var. maximum West. X 520 . 24 



20.$. leptodermum Lund. X 400 (after Lundell) . 27 



