LICHENS 
Family PyrenvLacgaz. 
Pyrenula gemmata (Ach.) Naeg. and Hepp. Trees. 
7 hyalospora (Nyl.) Tuckerm. 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. 
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