MIDDLESEX FLORA. 135 



CRYPTOGAM I A. 



PXERIDOPHYXES. 



EQUISETACEy^. HORSETAIL FAMILY. 



Equisetdm, L. 



E. arvense, L. Common Horsetail. 



Abundant. The var. serotinum, Meyer, has been found at 



Framingham (Miss J. W. Williams). 

 E. sylvaticum, L. 



Frequent. 

 E. limosum, L. 



Not very common. 

 E. hyemale, L. Scouring-Eush. Shave-Grass. 



Not very common. 



FILICES. FERNS. 



POLYPODIUM, L. 



P. vulgare, L. Polypody. 

 Common. 



Pteris, L. 

 P. aquilina, L. Brake. 

 Common. 



Adiantum, L. 



A. pedatum, L. Maidenhair. 



Generally distributed, but not abundant. 



WooDWARDiA, Smith. Chain Fern. 



W. angustifolia, Smith. 



Medford, one small station (R. Frohock). 

 W. Virginica, Smith. 



Maiden, Medford, Chelmsford, Ashby, et al. Not very common. 

 Asplenium, L. Spleenwort. 



A. Trichomanes, L. 



Once rather common, but becoming rare in the neigliborhood of 

 large towns. 



