172. Rinodina ] 43.- BU-ELLIACEAE 375 



A. Always on rocks 

 B. Thallus areolate 



C. Thallus brownish to black 



D. Thallus black 16. R. nigra 



D. Thallus brownish green or reddish brown 



E. Apothecia 0.2-0.4 mm. across 17. R. californica 



E. Apothecia 0.5-0.9 mm. across 34'. R. thysanota 



C. Thallus lighter colored 



D. Thallus greenish gray to ashy brown or grayish white to ashy 

 E. Disk blackish brown to black 

 F. Spores 1-septate 



G. Thallus very thin, soon disappearing .... 19. R. destitula 

 G. Thallus moderately thick, rough, persistent 

 H. Apothecia 0.3-0.8 mm. across, immersed 



1 or more in each areole 21. R. ocellata 



H. Apothecia 0.5-1.2 mm. across, adnate . . 18. R. tephraspis 

 F. Spores 3-septate, and becoming 1-septate 



longitudinally 29. R. microbola 



E. Disk more or less densely whitish pruinose .... 35. R. radiata 

 D. Thallus straw-colored to yellowish or brownish 



E. Thallus becoming lobed toward the circumference 

 F. Thallus greenish yellow to ashy 



G. Disk black 31. R. novomexicana 



G. Disk whitish pruinose 31. R. novomexicana caesia 



F. Thallus greenish straw-colored to yellowish . . . 30. R. oreina 

 E. Thallus not lobed toward the circumference 



F. Spores 12-16 X 6-10 n 20. R. euryspora 



F. Spores 20-25 X 9-11 /jl 22. R. ochrocea 



B. Thallus squamulose, granulose, or rarely smooth to chinky 

 C. Thallus granulose 



D. Spores 14-20 /j. in length 



E. Thallus dark greenish black or dirty gray to black 

 F. Thallus dark greenish black to black; 



apothecia 0.25-0.5 mm. across 12. R. aterrima 



F. Thallus dirty gray to dull black; 



apothecia 0.1-0.25 mm. across 10. R. kentuckyensis 



E. Thallus ashy or whitish to brownish 



F. Granules scattered upon a thin, black hypothallus, 



or passing into an areolate crust 13. R.milvina 



F. Granules commonly passing into a chinky, scurfy crust 



G. Apothecia 0.3-0.8 mm. across, sessile ... 14. R. Bischoffii 

 G. Apothecia 0.2-0.5 mm. across, immersed 14. R. Bischoffii immersa 



D. Spores larger, 18-32 n in length 28. R. Conradi 



C. Thallus not granulose 



D. Thallus smooth to chinky 7. R. Thomae 



D. Thallus squamulose 



E. Squamules yellow or yellowish to ashy 



F. Squamules minutely lobed; apothecia 0.3-0.8 mm. 



across 32. R. chrysomelaena 



F. Squamules broadly lobed; apothecia 1.5-3 mm. 



across 25. R. platyloba 



E. Squamules greenish gray to ashy 23. R. biatorina 



A. Not always on rocks 



B. Always on trees or old wood 



C. Apothecia not more than 0.5 mm. across 



D. Spores 8 in each ascus 5. R. milliaria 



D. Spores 8 or more in each ascus 



E. Thallus sometimes disappearing 26. R. exigua 



E. Thallus bordered and sometimes intersected by a 



black hypothallus 27. R. polyspora 



C. Apothecia rarely less than 0.5 mm. across 



D. Thallus greenish yellow to lemon-colored 4. R. lepida 



D. Thallus grayish white to ashy brown or brown 



E. Spores 14-20 X 6-9 fi 3. R. roboris 



