MIDDLESEX FLORA. 163 



NOSTOC, Vauch. 



N. sphaeroides, Kuetz. 



Cambridge (W. G. Farlow). 

 N. sphaericum, Vauch. 



Melrose, on rocks near the Cascade. 

 N. muscorum, Ag. 



Newton (W. G. Farlow). 

 N. collinum, Kuetz. 



Maiden, swamp in Middlesex Fells; Newton (W. G. Farlow). 



ANAB^ENA, Bory. 



A. Flos-aquae, Kuetz., var. circinalis, Kirchner. 



Horn Pond, Woburn (W. G. Farlow). 

 A. gigantea, Wood. 



Framingham (W. G. Farlow). 



SPH^EROZYGA, Ag. 



S. Carmichaelii, Harv. 

 Everett, salt marshes; Cambridge (W. G. Farlow). 



CYLINDROSPERMUM, Kuetz. 



C. majus, Kuetz. 



Newton (W. G. Farlow) ; Holliston, on walls of B. & A. R. R. 



tunnel, form resembling the C. comatum, Wood. 

 C. muscicola, Kuetz. 



Cambridge (W. G. Farlow). 



NODULARIA, Mertens. 



N. Harvey ana, Thuret. 

 Cambridge, salt marshes (W. G. Farlow). 



LYNGBYA, Ag. 



L. ochracea, Thuret. 



Cambridge (W. G. Farlow). 

 L. aestuarii, Liebm. 



Salt marshes, common. 

 L. luteo-fusca, Ag. 



Mystic river salt marshes. 

 L. Wollei, Farlow. 



Horn Pond, Woburn ; Lake Quannapowitt, Wakefield. 



MICROCOLEUS, Desmaz. 



M. chthonoplastes, Thuret. 

 Salt marshes, not uncommon. 



