142. Lecanora ] 38. LECANORACEAE 295 



F. Thallus more or less whitish pruinose . . . . 59. L. lentigera 

 B. Thallus crustose, not lobed toward the circumference 

 C. Apothecia immersed to adnate, disk concave to fiat 

 D. Spores rarely more than 15 n in length 

 E. Disk light-colored to becoming darker 

 F. Spores usually more than 10 n in length 



G. Thallus finely whitish pulverulent 2. L. iowensis 



G. Thallus chinky to areolate 



H. Spores 10-13 X 4-6 n ILL. odora 



H. Spores 11-17 X 6-9 /* 13. L. epulotica 



F. Spores 10 X 6 /i 14. L. lavata 



E. Disk reddish brown or black 



F. Thallus blackish olive 8. L. cinerea microspora 



F. Thallus not blackish olive 



G. Thallus pale brick color or yellowish green . . 12. L. lacustris 



G. Thallus greenish gray to ashy 9. L. deplanans 



D. Spores rarely less than 15 /a in length 

 E. Spores rarely more than 30 fi in length 

 F. Spores constantly 8 in an ascus 

 G. Disk black 



H. Apothecia 0.5-1.5 mm. across 



I. Thallus thin to thick, ashy white to 



greenish or rarely blackening 8. L. cinerea 



I. Thallus thick, greenish to brownish gray . 4. L. gibbosa 



H. Apothecia 0.2-0.6 mm. across 7. L. laevata 



G. Disk reddish to reddish brown ... 10. L. cinereorufescens 

 F. Spores 2-4 or 8 in an ascus 



G. Thallus greenish gray to rarely whitish . . . . 1. L. calcarea 

 G. Thallus greenish lead-colored or grayish 



white 3. L. contorta 



E. Spores commonly more than 30 m in length 



F. On trees; thallus dark ashy gray to yellowish . . 6. L. mutabilis 

 F. On soil and moss; thallus greenish gray to 



whitish or ashy 5. L. verrucosa 



C. Apothecia adnate to more or less sessile 

 D. Spores rarely more than 17 yu. in length 



E. Apothecia dark red, reddish brown to brown, or black 

 F. Thallus greenish gray to ashy, brownish, or more 

 or less yellowish 

 G. Confined to rocks 



H. Thallus greenish ashy to grayish or lead-colored 



I. Apothecia 0.4-0.9 mm. across 17. L. melaena 



I. Apothecia 0.8-1.8 mm. across 22. L. alpina 



H. Thallus greenish yellow 42. L. oregana 



G. Not confined to rocks 



H. On trees, old wood, and rocks 



I. Thallus rather thick, more or less granulose 



J. Disk very black 15. L. atra 



J. Disk brown to brownish black ... 23. L. rugosa 

 I. Thallus thin, becoming wrinkled and 



broken 26. L. subfusca coilocarpa 



H. On trees and old wood 



I. Apothecia 0.1-0.6 mm. across 



J. Thallus yellowish to ashy or darkening; 



disk reddish brown 38. L. effusa 



J. Thallus greenish gray to ashy; disk 

 reddish brown to brown and grayish 



pruinose 19. L. hypoptoides 



I. Apothecia 0.5-1 or 1.6 mm. across 



J. Disk reddish brown to brownish black 

 or rarely grayish pruinose; spores 



10-16 X 5-7.5 fi 36. L. parisensis 



J. Disk reddish brown and commonly grayish 



pruinose; spores 11-18 X 6-9 fi ■ • 20. L. miculata 



