154. Parmelia] 39 PARMELIACEAE 321 



tex, algal layer, and medullary layer of more or less loosely interwoven hyphae, 

 usually attached to the substratum by heavy rhizoids; apothecia small to large, 

 sessile or subpedicellate, the disk more or less concave to flat, usually brown, the 

 exciple colored like the thallus, prominent; hypothecium hyaline to brownish; 

 hymenium hyaline or brownish above; paraphyses rarely branched; asci clavate 

 or broadly clavate; spores commonly 8, rarely 2-6 or many, hyaline, subspherical 

 to oblong, ellipsoid or ovoid-ellipsoid, non-septate. 

 The algal host is Protococcus. 



A. Thallus greenish gray to grayish black 



B. Thallus light-colored to darker below, but not black 

 C. With coralloid branchlets or soredia above 



D. With coralloid branchlets above 1. P. rudecta 



D. With soredia above 



E. More or less covered by soredia 2. P. Borreri 



E. Marginally sorediate 5. P.hypotropa 



C. Without coralloid branchlets or soredia above 



D. Lobes broad; bearing light-colored rhizoids below ... 4. P. cubensis 



D. Lobes narrow; without rhizoids below 3. P.lanata 



B. Thallus brownish black to black below 

 C. Thallus inflated 



D. Thallus not perforated 



E. Thallus large, lobes dichotomously branched, 



margins becoming black 6. P.physodes 



E. Thailus smaller, lobes irregularly much-branched . . 7. P.encausta 



D. Thallus perforated by round or oblong holes 8. P.pertusa 



C. Thallus not inflated 



D. Thallus with coralloid branchlets or soredia above 

 E. Lobes broad 



F. With coralloid branchlets or rarely soredia above 

 G. Thallus densely covered with coralloid branchlets 



H. Bearing few scattered rhizoids below . . 9. P. coralloidea 



H. Bearing many rhizoids below 11. P. crinita 



G. Thallus bearing few coralloid branchlets and 

 sometimes sorediate 



H. Without soredia 10. P.latissima 



H. Margins sorediate 10. P. latissima sorediata 



F. With soredia above 



G. Bearing many, more or less scattered rhizoids 



H. Thallus becoming wrinkled above, bearing many 



soredia, especially toward the margins . . . 15. P. cetrata 

 H. Thallus bearing few marginal soredia . . . 13. P. olivaria 

 G. Bearing few or no rhizoids 



H. Margins bearing powdery soredia . . . . 14. P. perlata 

 H. Margins bearing rather large, globose 



soredia 12. P. cristifera 



E. Lobes narrow 



F. With coralloid branchlets above 



G. Coralloid branchlets small, more or less 

 spherical or cylindrical 

 H. Lobes more or less branched 



I. Thallus small, with few scattered 



rhizoids below 16. P. Finkii 



I. Thallus middle-sized to large, with 



many rhizoids below 18. P. saxatilis 



H. Lobes rarely branched, sometimes bearing 



fibrils 17. P. caroliniana 



G. Coralloid branchlets larger, flat and often 



lobed 19. P. frondifera 



F. With soredia above, sometimes rarely so 

 G. Without rhizoids below 



H. Papillate below 21. P. texana 



H. Reticulately pitted or finally perforate 



below 20. P. lophyrea 



