MipDLESEX FLORA. 



Glceothece, Naeg. 



G. confluens, ITaeg. 

 Newton (W. G. Farlow). 



Aphanothece, Naeg. 



A. prasina, A. Br. 



Cambridge (W. G. Farlow). 



CcELOSPaiEEiDM, Naeg. 



C. Kuetzingianum, Naeg. 

 Framingham (W. G. Farlow) ; Spot Pond, Stoneham. 



Clathkocystis, Henfrey. 



C. aeruginosa, Henfrey. 



Horn Pond, Woburn (W. G. Farlow) ; Spot Pond, Stoneham. 

 C. roseo-persicina, Cohn. 



Very common on salt marshes. 



GLtEOCAPSA, JTaeg. 



G. crepidinum, Thuret. 

 Everett and Medford, on woodwork near high-water mark. 



Chroococcus, Naeg. 



C. turgidus, Naeg. 

 Everett and Medford, with the preceding species. 



LICHENS. 



This list is undoubtedly far from being a complete catalogue of the 

 lichens of Middlesex County ; and the number of species would prob- 

 ably be double, if the same study could be given to this order as to 

 the flowering plants or ferns. As it stands, it is a list of species 

 known to occur here ; but the absence of any species from this list 

 does not at all imply that it does not grow in the county, or even 

 that it is very rare. In arrangement, nomenclature, etc., Tuckerman's 

 later works have been followed, which give a somewhat dififerent 

 system in the use of names of authorities for genera, species, etc., 

 from that employed in other orders. Unless otherwise stated, species 

 from Cambridge, Watertown, Newton, Medford, Arlington, and Lex- 

 ington are on the authority of Prof. Tuckerman ; from Waltham, 

 Mrs. S. E. French ; from Chelmsford, Eev. J. L. Eussell ; and species 

 fromNatick andSherborn were collected by Miss Clara E. Cummings, 

 to whom the writers are much indebted for a revision of the entire 

 list of lichens, as well as for additional species and localities. 



