xiv 



DESCRIPTION OF THE PLATES. 



11. Peltigera horizontalis, spore germinating. 



12. Peltigera polydactyla, section of young apothecium. 



13. Peltigera venosa, upper surface. 



14. Ditto, under surface. 



15. Ditto, spore. 



16. Nephroma resupinatum. — a. Upper surface, b. Under sur- 

 face, showing the apothecia. 



17. Ditto, margin of thallus, showing spermogones and nas- 

 cent apothecia. 



18. Ditto, marginal spermogone magnified. 



19. Ditto, section of ditto. 



20. Ditto, spore. 



21. Ditto, sterigmata and spermatia. 



PLATE X. 



1. Umbilicaria pustulata, upper surface. 



2. Ditto, under surface. 



3. Ditto, section of apothecium. 



4. Ditto, muriform spore. 



5 . Ditto, section of apothecium, a, and of thallus, showing a 

 spermogone, h. 



6. Ditto, section of thallus, showing a spermogone, a, and a 

 pustular elevation, b. 



7. Ditto, sterigmata and spermatia. 



8. U. polymorpha, common ciliated variety, upper surface. 



9. Ditto, under surface, showing point of attachment, a. 



