PLATE CXL1V. 



FIGS. PAGE 



1-2. Staurastrum subgracillimum W. & G. S. W. 1, 

 from Ireland, X 520 : 2, from the United States, 

 X 520. . . . .118 



3-7 . S* gracile Ralfs. 3*, X 510 ; 4, x 520 ; 5*, X 

 510 ; 6*, a form, X 510 (det. G. S. West) ; 7 

 zygospore, X 520 . . .96 



8-9. St. gracile var. nanum Wille. 8, X 400 9, X 520 100 

 10. St. gracile var. coronulatum Boldt. X 520 . 100 

 11. St. gracile var. tenuissima Boldt. X 500 (after 



Boldt) . . . .100 



12. St. gracile var. cyathiforme W. & G. S. W. X 520. 99 

 13. St. gracile var. bulbosum West. X 400 . 98 



