12 BRITISH LICHENS : 



85. Thelopsis Nyl. Thallus scarcely any visible, containing 

 chrysogonidia : apothecia tuberculoso-spherical, with entire py- 

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



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

 thallus of Collemei, endocarpoid, with simple or septate corniculate 

 spores ; spermogones unknown. 



^ 87. Strigula Fr. Thallus maculate, hypophlceodal, seldom effigu- 

 rate, containing platygonidia : apothecia subinnate, with the 

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

 spermogones with thin straight spermatia. 



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

 carioid, numerous and confluent in the pyrenia, with septate 

 spores : spermogones not observed. 



Series VII. PERIDIODEI Nyl. Thallus thin, often wanting : 

 apothecia peridieine, without any ostiole. 



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

 proper : apothecia forming a peridium. 



89. Thelocarpon Nyl. Thallus crustaceous, thin, verrucose, or 

 rarely none : apothecia immersed in the thalline verrucas, with 

 numerous simple spores ; spermogones unknown. 



90. Endococcus Nyl. Thallus none proper : apothecia minute, 

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

 spermatia. 



91. Mycoporum Flot. Thallus maculate or obsolete : apothecia 

 rotundato-difform, containing many hymenia conjoined as in a 

 common exciple, with variously septate spores; spermogones not 

 observed. 



Family IV. MYBIANGIACEI Nyl. Thallus unstratified, 

 entirely cellular ; thalamium cellular, with superimposed theciferous 

 cavities : fructification not discrete. 



92. Myriangmm Mont. & Berk. Thallus noduloso-pulvinate : 

 apothecia sublecanorine, with irregularly septate spores; spermo- 

 gones not seen. 



