MIDDLESEX FLOKA. 169 



NEPHROMA, Ach. 



N. tomentosum, (Hoffm.) Koerb. 

 Waltham. 



N. Helveticum, Ach. 

 Chelmsford, Medford, Lexington, Natick. 



PELTIGERA, (Willd., Hoffm.) F6e. 



P. aphthosa, (L.) Hoffm. 



Waltham (C. J. Sprague). 

 P. polydactyla, (Neck.) Hoffm. 



Waltham. 

 P. rufescens, (Neck.) Hoffm. 



Cambridge, Waltham. 

 P. canina, (L.) Hoffm. 



Waltham. 

 P. canina, (L.) Hoffm., var. sorediata, (Schaer.) 



Waltham. 



PHYSMA, Mass. 



P. luridum, (Mont.) 

 Waltham. 



P ANN ARIA, Delis. 



P. lanuginosa, (Ach.) Koerb. 



Waltham. 

 P. molybdea, (Pers.) Tuck., var. cronia, Nyl. 



Waltham. 



COLLEMA, Hoffm., Fr. 



C. verruciforme, Nyl. 



Cambridge. 

 C. flaccidum, Ach. 



Waltham. 



LEPTOGIUM, Fr., Nyl. 



L. pulchellum, (Ach.) Nyl. 



Waltham. 

 L. Tremelloides, (L. fil.) Fr. 



Medford, Waltham, Natlck. 

 L. myochroum, (Ehrh., Schaer.) Tuck., var. saturninum, 



Schaer. 



Chelmsford, Cambridge, Watertown, Waltham (Tuckerman). 



PLACODIUM, (DC.) Naeg. & Hepp. 



P. elegans, (Link) DC. 

 Cambridge. 



