106 



Potamogeton pusillus, L. 



Marblehead (Ker. J. L. Eussell), Danversport, in brackish water; 



outlets of Wenham and Cliebacco ponds. 

 Var. tenuissimus, Mertens & Koch. 



Wenham pond. 

 Potamogeton gemmiparus, Bobbins, Potamogeton pnsillus, 



var. (?) gemmiparus. (Gray's Manual). 



Wenham pond. 

 Potamogeton Bobbinsii, Oakes. 



"Wenham pond, 1829" (Oakes in Hovey's Mag., Vol. VII), the 



original discovery ; Crane pond, West Newbury ; Sluice pond, and 



abundant in Max pond (C. E. Faxon). Single specimens have been 



noticed at Pleasant pond, Wenham, and Ipswich river. It varies 



to small forms. 

 Potamogeton crispus, L. 



Spy pond, Arlington, 1880 (C. E. Eaxon). Probably introduced. 



ALISMACE.S!. 



(Water-Plantain Family.) 



Triglochin maritimum, L. 



Salt marshes. Common. 



Scheuchzeria palustris, L. 

 "Wenham swamp, 1824" (memo. Dr. Chas, Pickering). 



Alisma Plantago, Z., var. Amerieanuin. 



Wet places along roadsides and railroad beds. Common. 



Echinodorus parvulua, Engelm. 

 Near Cambridge (Prof. James) ; Winter pond, Winchester (E. H. 

 Hitchings). This little plant ought to be found within the limits 

 of the county as It occurs so near us. 



Saglttaria variabilis, Engelm. 



A plant of many forms. 

 Var. obtusa. 



Georgetown (Mrs. Horner) ; Essex, etc. Quite common. 

 Var. latifolia. 



Brooks and meadows. Frequent. 

 Var. hastata. 



Ditches, etc. This is the most common form. 

 Var. diversifolia. 



Pleasant pond, Wenham. 



