MIDDLESEX FLOKA. 139 



ISOETE^E. QUILLWORT FAMILY. 



ISOETES, L. QUILLWORT. 

 I. lacustris, L. 



Fresh Pond, Cambridge (Wm. Boott). An unusually southern 



station for this species. 

 I. Tuckermani, A. Br. 



Mystic River and Fond (E. Tuckerman), the original station; Horn 



Pond, Woburn (Wm. Boott) ; Spy Pond, Arlington (Rev. Thos. 



Morong) . 

 I. echinospora, Durieu, var. Braunii, Engelm. 



Not uncommon. 

 I. echinospora, Durieu, var. Boottii, Engelm. 



Round Pond, Woburn, the original station ; Tofit swamp, Lexing- 

 ton (Wm. Boott). 

 I. echinospora, Durieu, var. muricata, Engelm. 



Woburn Creek and Abajona River, the original locality, not 



uncommon (Wm. Boott) ; Bedford (C. W. Jenks) ; So. Natick 



(Rev. Thos. Morong) ; Lexington (Wm. Boott). 

 I. riparia, Engelm. 



So. Natick (Rev. Thos. Morong). 

 I. Engelmanni, A. Br. 



Arlington Brook; Alewife Brook, Woburn (Wm. Boott). 



MARSILIACE/E. WATER-FERN FAMILY. 

 MARSILIA, L. 



M. QUADRIFOLIA, L. 



Concord, Bedford, Belmont, Cambridge, et al. Int. and nat. from 

 farther south. 



BRYOPHYTKS. 



MUSCI. MOSSES. 



The following list is founded principally on the collections of 

 Mr. H. A. Young, Mrs. S. E. French, Miss C. E. Cummings and 

 Messrs. Edwin and Charles E. Faxon, with additional species from 

 the published lists of Mr. T. P. James and Rev. J. L. Russell. 



