DESCRIPTION OF THE PLATES. 



ix 



taming spores or protoplasm, c. Hypothecium. d. Gonidia. 

 e. Medullary filaments. /. Cortical layer of thallus. g. Spore 

 under action of iodine. 



2. Spermogone of Parmelia ceratophylla, var. physodes. 



3. Sterigmata of the same Lichen. 



4. Spermatia, ditto. 



5. Sterile spermogonal filaments, ditto. 



6. Sterigmata and spermatia of Sticta pulmonaria. 



7. Ditto ditto of Calicium turhinatum. 



8. Ditto ditto of Lecanora atra. 



9. Ditto ditto of Lecanora subfusca. 



10. Ditto ditto of Urceolaria scruposa, 



11. Sterigmata and spermatia of Lichina pygmcea. 



12. Ditto ditto, of Ramalina fraxinea. 



13. Pycnides of Scutula WallrotMi. 



14. Sterigmata and stylospores of ditto. 



PLATE III. 



1. Usnea barhata, common form. 



2. Ditto, apothecium showing fibrillose-radiate margin. 



3. Ditto, section of apothecium magnified. 



4. Ditto, var. articulata, showing the inflated and articulated 

 condition of the thalline filaments. 



5. Ditto, var. plicata, also showing articulated condition of 

 thalline filaments. 



