OF 1 GREAT BRITAIN. 3 



Thallus membranaoeo-lobate, tomentose and cyphellate 

 beneath ; spores fusiform, 1-3-septate ; paraphyses distinct. 

 = Sub-tribe 1. Stictei. 



TJiallus laciniato-lobate ; spores ellipsoid, simple ; para- 

 physes indistinct. = Sub-tribe 2. Imbricariei. 



Thallus stellato-orbicular ; spores bilocular ; paraphyses 

 distinct. = Sub-tribe 2. Physciei. 

 Apothecia lecideine, gyrose. = Tribe XIII. Gyrophorei. 



Series V. PLACODEI. 



Apothecia lecanorine. = Tribe XIV. Lecanorei. 



Thallus squamulose, gonidia large, distinct. = Sub-tribe 1 . 

 Psoromei. 



Thallus squamulose or granuloses with granula gonima 

 (no gonidia). = Sub-tribe 2. Pannariei. 



Thallus pulverulent. = Sub-tribe 3. Amphilomei. 

 Thallus radioso-laciniate or cartilagineo-squamose ; spores 

 ellipsoid, simple. = Sub-tribe 4. Squamariei. 



Thallus radiate (not radioso-laciniate) ; spores ellipsoid, 

 bilocular, cells united by a longitudinal tube. = Sub-tribe 

 5. Placodei. 



Thallus crustaceous,granulose ; spores simple or variously 

 septate. = Sub-tribe 6. Eulecanorei. 



Apothecia endocarpoid, enclosed in verrucas of thallus ; 

 spores very large, ellipsoid. = Sub-tribe 7. Pertusariei. 



Apothecia in thalline verrucse, but with an open epithe- 

 cium ; spores plurilocular or murali-divided. = Sub-tribe 8. 

 Thelotremei. 

 Apothecia biatorine or lecideine or gyalectine. = Tribe XV. 

 Lecideinei. 



Apothecia lirelline. = Tribe XVI. Graphidei. 

 Hymenia covered by a black rimuloso-dehiscent peridium. = 

 Tribe XVII. Peridiei. 



Series VI. PYRENODEI. 



Apothecia pyrenodine. = Tribe XVIII. Pyrenocarpei. 



Fam. I. BYSSAOEI. 



Tribe I. Sirosiphei. 



Thallus csespitose, distinctly vaginate. = Sirosiphon. 

 Thallus csespitose, granula gonima concatenate into a central 

 axis ; apothecia biatorine. = Gonionema. 



Fam. II. COLLEMACEI. 



Tribe 1. Liohinei. 



Thallus csespitose, granula gonima in transverse strata; apo* 

 thecia lecideine. = Spilonema 



