12 BEITISH LICHENS : 



85. Thelopsis Xyl. Thallup scarcely any visible, containing 

 chrysogonidia : apothecia tuberculoso-splierical, with entire py- 

 renium and numeroiis 3-septate spores ; spermogones not seen. 



86. Obryznm TVallr. Thallus none proper : apothecia on the 

 thallus of CoUemei, endocarpoid, with simple or septate corniculate 

 spores ; spennogones unknown. 



^ 87. Strigxila Fr. Thallus maculate, hypophloeodal, seldom effigu- 

 rate, containing platj^gonidia : apothecia subinnate, with the 

 pyrenium usually depressed, and with simple or 1-3-septate spores ; 

 spermogones with thin straight spermatia. 



88. Melanotheca Fee. ThaUus scarcely any: apothecia verru- 

 carioid, numerous and confluent in the pyrenia, with septate 

 spores : spermogones not observed. 



Series YII. PERIDIODEI I^yl. ThaUus thin, often wanting : 

 apothecia peridieine, without any ostiole. 



Tribe XXI. PERIDIEI jSTyl. Thallus thin, maculate or none 

 proper : apothecia forming a peridium. 



89. Thelocarpon Xyl. ThaUus crustaceous, thin, verrucose, or 

 rarely none : apothecia immersed in the thaUine verrucse, with 

 numerous simple spores ; spennogones unknown. 



90. Endococcus Xyl. ThaUus none proper : apothecia minute, 

 globulose, with 1-septate spores ; spermogones with thin straight 

 spermatia. 



91. Mycoporum Flot. ThaUus maculate or obsolete : apothecia 

 rotundato-diffonn, containing many hymenia conjoined as in a 

 common exciple, with variously septate spores ; spermogones not 

 observed. 



FamUy IV. MYRIANGrlACEI Xyl. ThaUus unstratified, 

 entirely ceUular ; thalamium ceUular, with superimposed theciferous 

 cavities : fructification not discrete. 



92. Myriangium Mont. & Berk. ThaUus noduloso-pulvinate : 

 apothecia sublecanorine, with irregularly septate spores ; spermo- 

 gones not seen. 



