DESCRIPTION OP THE PLATES. 



xvii 



19. P. late-virens, var. herbacea, spore. 



20. P. stellaris, spore. 



21. Ditto, under action of iodine. 



22. P. olivacea, mature and young spores. 



PLATE XIII. 



1. Lecanora Villarsii (foreign species), vertical section of thal- 

 lus, showing an apothecium, a, and a spermogone, b. 



2. Ditto, section of spermogone. 



3. Ditto, spermatia. 



4. Z. orostkea, section of a spermogone. 



5. Ditto, sterigmata and spermatia. 



6. L. tartar ea. 



7. Ditto, section of an apothecium. 



8. Ditto, young apothecia, magnified. 



9. Ditto, symphycarpeous or confluent apothecia. 



10. L. subfusca. 



11. Ditto, section of young apothecium, showing its concave 

 condition. 



12. Ditto, section of old apothecium, showing its convex con- 

 dition. 



13. L. pallescens, var. parella. 



14. Ditto, young apothecia, magnified. 



15. Ditto, section of an apothecium. 



16. Ditto, spores in the earlier stages of development. 



17. L. atra. 



b 



