I 66 HERRE 



Occurring with us only on rocks, but common in the maritime 

 region. Our plant is the form rupestris of authors but is not to be 

 separated from the type. A tree and rock lichen of common occur- 

 rence throughout Europe and America. 



2. PERTUSARIA AMARA (Ach.) Nyl. 



Variolaria amara Acharius, Lich. Univ. 324. 18 10. 

 Pertusaria amara Nylander, Flora, 22. 1873. 



Thallus from determinate and orbicular becoming widespread 

 and effuse; rough and chinky, more or less powdery, usually densely 

 covered with large, often confluent soredia; color gray to almost 

 white, marginally brown and zonate; KOH — ; the apothecial ver- 

 rucae becoming sorediate heaps with us and the plant therefore 

 sterile; when treated with KOH + CaCl202 they give a violet reac- 

 tion. 



The whole plant very bitter, almost like quinine. 



Abundant on trunks of trees, especially on ^sculus and Quercus. 



A common lichen in Europe and recorded also from Japan, but 

 apparently not distinguished by American authors. 



3. PERTUSARIA GLOBULIFERA (Turn.) Nyl. 



Variolaria globulifera Turner, Trans. Linn. Soc. 9: 139. 1808. 

 Pertusaria globulifera Nylander, Mem. Soc. Cherbourg, 5: 116. 

 1857- 



Thallus sub-orbiculate but spreading extensively and then more 

 or less indeterminate; cartilaginous; smooth at first but soon un- 

 evenly plicate and more or less fissured; sprinkled with minute white 

 soredia; color gray to white; marginally zonate and brown, but 

 less marked than in P. amara. 



Apothecial warts adnate, plane, lecanoroid, sterile, degenerate, 

 passing into white, powdery heaps, the central portion of the thallus 

 soon almost covered with the dense confluent soredia; KOH — ; 

 CaCl202 — . 



Common on tree trunks in the mountains and widely distributed 

 in Europe and North America. 



