6 LICHENS OF THE STATE OF WASHINGTON 



black 12. Lecanactis 



29. Spores not hyaline, gray, or brown. 



37. Spores with a distinct gelatinous halo 37. Rhisocarpon 



37. Spores without a distinct gelatinous halo 67. Buellia 



25. Spores muriform. 

 38. Spores hyaline. 



39. Usually growing on bark; numerous crater-like apothecia 



13. Thclotrema 



39. Not as above. 



40. Always growing on rock; spores not more than 20 m long 



16. Gyalecta 

 40. Growing on trees and encrusting mosses on rocks; spores 



more than 40 /^ long 36. Lopadium 



38. Spores brown. 



41. Thalline margin disappearing early, spores without a gelatinous 



halo 14. Diploschistes 



41. Thalline margin absent entirely, spores with a distinct gela- 

 tinous halo ^7. Rhisocarpon 



SQUAMULOSE OR FOLIOSE 



1. Podetia present (thallus usually twofold, consisting of a primary squamulose or 

 foliose thallus that often disappears, and a secondary thallus consisting of erect 



podetia) 40. Cladonia 



1. Podetia absent. 

 2. Thallus more or less gelatinous when moist. 



3. Thallus decidedly gelatinous when moist, brittle when dry; algal component 

 Nostoc. 



4. Both upper and lower cortices lacking 19. Collema 



4. Both upper and lower cortices present or only the upper cortex present.....^ 



20. Leptogium 

 3. Thallus not so decidedly gelatinous when moist, brittle when dry; algal com- 

 ponent Scytonema 18. Polychidium 



2. Thallus not gelatinous when moist. 

 5. Spores borne in a perithecium. 



6. Thallus umbilicate, rather large, foliose; spores hyaline, nonseptate 



4. Dermatocarpon 



6. Thallus not umbilicate, smaller, squamulose. 



7. Squamules very small ; perithecia rare ; spores hyaline or brownish, septate. 



3. Normandina 

 7. Squamules not very small ; perithecia not rare ; spores hyaline, nonseptate. 



4. Dermatocarpon 



5. Spores borne in an apothecium. 

 8. Thallus squamulose. 



9. Apothecia borne in a stroma; disk black; spores 1-septate 8. Arthonia 



9. Apothecia not borne in a stroma. 



10. Usually a green algal component, very rarely a blue-green. 

 11. Thalline margin conspicuous, permanent. 



12. Spores small to very small, asci often 100-spored. 



13. Thallus with an upper cortex, usually marginally lobed 



44. Acarospora 



13. Thallus without an upper cortex, usually not marginally lobed. 



51. Candelariella 

 12. Spores neither very large nor very small. 



14. Spores hyaline. 



15. Spores nonseptate. 



