PLATE VII. 



FIGS. PAGE 



1-2. Netrium interruptum (Breb.) Liitkem. 1, x 



400; 2, x 520. . . .68 



3. N. interruptum var. sectiuu West. x 300 . 69 

 4-5. JV. Xagelii (Breb.) West & Cl. S. West. x 520 66 

 6-7. Prninin Lihrlltila (Focke) Nordst. 6, x 400; 



7, x 220 . . . 7:5 



8. P. Lilrlhtla forma. x 400 . 74 



9-10. P. Libellnla var. intrrru^/ mil West & Cl. S. 



West, x 520 . . . .74 



11. P. Libellula var. intermedium Roy & Biss. x 



520 . . . . .74 



12-15. P. Navirtila Breb. 12, x 400; 13-15, x 520. 75 

 HS-17. P. Navicitla var. crrtxxnm West & Cl. S. West. 



x 520 . . . .76 



18. P. Narlcnla var. iujlntnm West & G. S. West. 



x 400 . . . . 77 



19. P. NavicuJa. Zygospore, after Lundellj x 400 75 

 20-21. P. Jennerl Ralfs. After Ralfs, x 200; 21, 



zygospore . 77 



