LICHENS OF THE STATE OF WASHINGTON 9 



surface 55. Cetraria 



54. Thallus flat, prostrate; rhizoids usually abundant, rarely lack- 

 ing on the lower surface. 54. Parmelia 



FRUTICOSE 



1. Podetia present (thallus usually twofold, consisting of a primary crustose, squamu- 

 lose, or foliose thallus that often disappears, and a secondary thallus consisting of 

 erect podetia). 

 2. Podetia short, often poorly developed, usually simple. 

 3. Apothecia black 39. Pilophoron 



3. Apothecia light-colored. 38. Baeomyces 



2. Podetia longer, well developed, usually branched. 



4. Podetia solid, cephalodia common 41. Stereocaulon 



4. Podetia usually hollow, simple or branched. 



5. Podetia always white or ashy, simple or sparingly branched, apothecia un- 

 known 63. Thamnolia 



5. Podetia not always white or ashy, simple or abundantly branched, apothecia 



usually present, disk brown, reddish brown, or scarlet 40. Cladonia 



1. Podetia absent. 

 6. Apothecia stalked. 



7. Stalk long, well developed. 5. Calicium 



7. Stalk short, sometimes lacking. 

 8. Thallus greenish, resembling a layer of paint; disk pale flesh color (R) or 



rosy pink 48. Icmadophila 



8. Thallus grayish, disk dull black 6. Cyphelium 



6. Apothecia not stalked. 



9. Thallus gelatinous when moist, brittle when dry; always a blue-green algal 



component 20. Leptogium 



9. Thallus not gelatinous when moist. 



10. Thallus dark green, dark brown, or black. 

 11. Thallus consisting of small, fine hair or thread-like masses. 

 12. Blue-green algal component; fungal hyphae entirely within the algal 

 filament 17. Thcrmutis 



12. Green algal component; fungal hyphae not within the algal filament. 



54. Parmelia 

 11. Thallus consisting of large, coarse hair or string-like masses, erect, pro- 

 cumbent, or pendulous 59. Alectoria 



11. Thallus shrub-like, membranaceous, erect, depressed, or procumbent. 



13. Lower cortex rarely developed, thalline margin absent 31. Lccidea 



13. Lower cortex well developed, thalline margin present. 



14. Thallus dark brown or black on both surfaces, apothecia scattered on 



upper surface 54. Parmelia 



14. Thallus dark brown, greenish black, or black on upper surface, lighter 



below, apothecia marginal 55. Cetraria 



13. Cortex extending all the way around the thallus, thalline margin present. 



60. Comicularia 

 10. Thallus light brown, brown, or yellow. 

 15. Medulla cottony. 

 16. Apothecia originate on the lower surface of the thallus, but by the 

 turning of the lobes of the thallus appear to grow on the margin of 



the upper surface 56. Nephromopsis 



16. Apothecia originate on the margin of the upper surface of the thallus. 



55. Cetraria 



15. Medulla stiff or cobweb-like, thallus always some shade of yellow. 



58. Letharia 



