174 MIDDLESEX FLORA. 



Ptkbnula, (Ach., Naeg. & Hepp.) Tuck. 



P. punctiformiSj (Ach.) Naeg. 



Cambridge. 

 P. gemmata, (Ach.) Naeg. 



Sherborn. 

 P. thelaena, (Ach.) Tuck. 



Natick. 



