DESCRIPTION OF THE PLATES. 



xix 



17. L. sanguinaria, theca and its protoplasm, bringing only 

 one spore to maturity. 



18. Ditto, mature normal spore. 



19. Ditto, spores rendered abnormal by adherent, abortive, or 

 rudimentary spores. 



20. L. decvpiens ; thallus, magnified, showing the relative 

 position of the spermogones, b. 



21. Ditto, section of an apothecium, a, and of thallus, show- 

 ing a spermogone, b. 



22. Ditto, sterigmata and spermatia. 



23. L. granulosa , var. decolor ans, spore. 



24. L. punctata, var. punctiformis, spore. 



25. L. quernea ; spores, young and old. 



26. L. pineti, spore. 



27. L. fusco-lutea, spore. 



PLATE XV. 



1. Opegraplia saxatilis ; section of thallus, showing an apo- 

 thecium, a, and a spermogone, b. 



2. Ditto, section of a spermogone, showing the sterigmata 

 and spermatia. 



3. 0. varia, var. not ha. 



4. Ditto, lirellae, magnified. 



5 . Gracilis jmlverulenta. 



6. Ditto, a lirella magnified. 



7. Ditto, section of a lirella, showing perithecium or exciple, a, 

 and thalamium or nucleus, b. 



