LICHENS 



s 



Family PYRENULACEAE. 



Pyrenula gemmata (Ach.) Naeg. and Hepp. Trees. 

 " hyalospora (Nyl.) Tuckenn. Trees. 

 " leucoplaca (Wallr.) Koerb. Trees. 



REFERENCES. 



Fink. The Lichens of Minnesota. Smithsonian 



Inst. Washington. 1910. 

 Tuckerman. North American Lichens. Boston. 



1882. 

 Schneider. A Text-book of General Lichenology. 



Binghampton, N.Y. 1897. 



187 



