PLATE CXLII. 



FIGS. PAGE 



1-7. Staurastrum brachiatum Ralfs. 1-6, x 520 ; 7, 



zygospore, X 520 . . .88 



8.- St. inconspicuum Nordst. X 500 (after Borgeson) 86 

 9-10. *. fmnconicum Reinsch. 9, X 750 ; 10, x 625 



(both after Reinsch) . . .85 



11-14. &. Jiexacerum (Ehr.) Wittr. 11, 12, and 13, X 520 ; 



14, zygospore X 400 (after Ralfs) . . 138 



15. St. hexacerum var. semicirculare Wittr. X 400 (after 



Wittrock) . . . .139 



16-18. iS^. neglectum G. S. West. 16, X 500 ; 17, X 840 

 (vertical view) ; 18, zygospore, X 400 (after 

 Ralfs) . . . . .111 



19-20. St. Haaboeliense Wille. 19, X 520 ; 20, X 500 . 140 

 21-22. St. brachycerum Breb. 21, x 520 ; 22*. x 810 . 136 

 23. S*. affine W. & G. S. W. X 520 . 128 



24. St. polymorphum Breb. Zygospore, X 600 (from 



a drawing by Dr. Lutkemiiller) . . 125 



