322 39. PARMELIACEAE [ 154. Parmelia 



G. With numerous black rhizoids below .... 22. P. sulcata 

 D. Thallus without coralloid branchlets or soredia above 

 E. Lobes broad 



F. Without rhizoids below 



G. Margins bearing numerous black cilia ... 24. P. subrugata 

 G. Margins sometimes bearing few black cilia . 23. P. submarginalis 

 F. With rhizoids below 



G. Margins sometimes bearing short cilia; 

 apothecia commonly perforate 

 H. Lobes more or less branched and 



imbricated 25. P. perforata 



H. Lobes sometimes extending into narrow 



flat divisions 26. P. hypotrypodes 



G. Margins rarely bearing cilia ; apothecia not 



perforate 27. P. proboscidea 



E. Lobes narrow 



F. Thallus bearing few to many rhizoids below ; 

 spores constantly 8 in each ascus 

 G. Thallus whitish within 



H. Thallus greenish gray to whitish 

 I. Lobes short to elongated 



J. Lobes subdichotomously branched . . 30. P.quercina 

 J. Lobes subpinnately branched and 



elongated 29. P. sublaevigata 



I. Lobes shorter and narrower ... 30. P. quercina minor 

 H. Thallus black to greenish olivaceous or 



dark greenish gray 28. P. atrofusca 



G. Thallus sulphur-yellow within 31. P. sulphurosa 



F. Thallus covered below with a dense, spongy nap ; 



spores many in each ascus 32. P. colpodes 



A. Thallus straw-colored or yellowish green or brown 

 B. Light-colored to darker below, but not black 



C. Lobes broad 33. P. sphaerosporella 



C. Lobes narrow 



D. Without soredia above 



E. On trees; lobes flat, somewhat branched 



and imbricated 34. P. leucochlora 



E. On rocks; lobes convex, much branched .... 35. P. centrifuga 



D. With raised powdery soredia above 36. P. incurva 



B. Brownish black to black below 

 C. Lobes broad 



D. Rhizoids scanty or absent 



E. Bearing few scattered rhizoids below 



F. With soredia above 37. P. flavicans 



F. Without soredia above 38. P. praesignis 



E. Bearing minute, black tubercles below . .... 39. P. arizonica 



D. Rhizoids usually present 



E. Rhizoids few, not at the margins 



F. Thallus bearing coralloid branchlets breaking 



up into soredia 40. P. caperata 



F. Thallus bearing powdery soredia 41. P. ulophylla 



E. Rhizoids few to many, to the margins 



F. Thallus sulphur-colored or yellowish within 



G. Bearing granules or coralloid branchlets . . 42. P. sulphurata 



G. Bearing soredia 43. P. aurulenta 



F. Thallus whitish within 44. P. soredica 



C. Lobes narrow 



D. Thallus closely adnate 



E. On trees; spores 8-10 X 4-5 /* 45. P. scortella 



E. On rocks and rarely on old wood; spores 



8-12X4.5-7/* 46. P. conspersa 



D. Thallus loosely adnate or subfruticose 



E. Thallus loosely adnate 47. P. laevigata 



E. Thallus subfruticose 48. P. molliuscula 



