155. Cetraria] 39. PARMELIACEAE 335 



C. Lobes somewhat broad to narrow, more or less channeled 



or pitted, repeatedly divided above 15. C. nivalis 



B. Thallus greenish gray to brownish or blackening 

 C. Thallus without spinules 



D. Lobes round to compressed in section 20. C. tristis 



D. Lobes flat 16. C. californica 



C. Thallus with spinules 



D. Lobes round to compressed in section 19. C. aculeata 



D. Lobes expanded with inrolled margins 



E. Margins thickly spinulose, usually with soredia below . 17. C.islandica 

 E. Margins spinulose above, entire below without soredia . 18. C. hiascens 



1. Cetraria glauca (L.) Ach., Meth. Lich. 296,297. 1803. 

 Lichen glaucus L., Sp. PI. 1148. 1753. 



Thallus middle-sized to large, foliose. wavy to laciniately lobed, greenish gray 

 iately lobed, the lobes irregular, narrow to linear, elongated, often much branched, 

 smooth to lacunose, the margins often ascending, entire to crenate, often jagged 

 or curled, the edges sometimes prolonged into coralloid branchlets, frequently 

 sorediate; pale to dusky brown, becoming black, more or less wrinkled, sometimes 

 with rhizoids below; apothecia rare, middle-sized to large, 6-14 mm. across, adnate, 

 marginal to submarginal, the disk chestnut-brown, the exciple irregular and disap- 

 pearing; spores ellipsoid, 4.5-9 X 3.5-5 /a. 



On trees and old wood, across the northern portion of the United States. 



2. Cetraria Tuckermani Herre, Proc. Wash. Acad. Sci. 7:340. 1906. 



C. glauca var. stenophylla Tuck, name preoccupied. 



Thallus middle-sized to large, foliose, greenish gray to pale yellowish, lacin- 

 iately lobed, the lobes irregular, narrow to linear, elongated, often much branched, 

 smooth to channeled or lacunose, the margins often ascending, entire to crenate, 

 often jagged or curled, frequently sorediate; pale to dusky brown, becoming black, 

 usually reticulate-lacunose below; sterile. 



On trees, Washington, Oregon, and California. 



3. Cetraria Oakesiana Tuck., Bost. Journ. Nat. Hist. 3:445. 1841. 



Thallus small, foliose, greenish gray to straw-colored, irregularly lobed, the 

 lobes loosely separated to compact, often long, branched, flat to curled, the mar- 

 gins often undulate, entire to somewhat crenulate, whitish sorediate; brownish with 

 dark rhizoids below; apothecia marginal, small to middle-sized, 2-6 mm. across, 

 sessile, the disk concave to irregular; spores round-ellipsoid to longer, 5-10 X 

 4.5-6 /a. 



On trees and rocks, New Hampshire, Massachusetts, New York, Maryland, the 

 Carolinas, and Georgia (rarely fertile except in alpine areas). 

 var. spinulosa Merrill, Bryologist 13:25. 1910. 



Thallus marginally beset with scattered or abundant, short to somewhat elon- 

 gated, dentate spinules. 



On trees, West Virginia (description compiled). 



4. Cetraria juniperina (L.) Ach., Meth. Lich. 298. 1803. 



Lichen juniperinus L., Sp. PI. 1147. 1753. C . juniperina var. pinastri (Scop.) 

 Ach. C. juniperina var. terrestris Schaer. C. viridis Schwein. C. juniperina 

 var. virescens Tuck. 



Thallus small to middle-sized, foliose, greenish gray to straw-colored, the lobes 

 small, narrow, irregularly divided, crowded, more or less lacunose, ascending, the 

 margins curled, irregularly notched, crenate, often yellow-sorediate ; paler to nearly 

 the same color below; apothecia small to middle-sized, 2-6.5 mm. across, sub- 

 marginal, sessile to subpedicellate, the disk concave to convex, chestnut-brown, 

 exciple crenulate; spores subspherical to ellipsoid, 4.5-8 X 4-5.5 /a. (Plate 36 a.) 



On rocks, soil, trees, and old wood, widely distributed throughout northern 

 United States. 



