PLATE CXXXVII. 



FIGS. PAGE 



1-2. Staurastrum gladiosum Turn. 1, X 400 ; 2, X 



520 . . . . . 57 



3. St. gladiosum var. delwatulum W. & G. S. W. X 



520 . . . . .58 



4-5. St. Brebissonii Arch. 4, X 600 (from a drawing by 

 Dr. Lutkemuller) ; 5, zygospore, X 720 (after 

 Cleve) . . . .61 



6. St. Brebissonii var. brevispinum West. X 400 . 63 

 7. St. Saxonicum Bulnh. X 400 (after Roy & Biss.) 54 

 8. St. Picum W. & G. S. W. X 520 . .51 



9-11. St. erasum Breb. 9, X 430 ; 10 and 11, X 520 . 71 

 12. St. echinatum Breb. X 600 (from a drawing by Dr. 

 Lutkemuller from de Brebisson's original exsic- 

 cata) . . . . .56 



13-14. St. cumbricum West. X 400 . . 55 



15-16. St. cumbricum var. cambricum West. 15, X 400 ; 



16, forma minor, X 400 . . .56 



