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Potamogeton Oakesianus, Robbins. 
Foster’s pond, Beverly, 1873 (J. R.); Sluice pond, Lynn (Edwin 
Faxon). 
Potamogeton Claytonii, Tuckerman. 
Ponds and brooks. Common. 
Potamogeton Spirillus, Tuckerman. 
Old mill brook, Boxford; Merrimac river at Lawrence, Georgetown. 
There is a variety, with no floating leaves, in Chebacco pond. 
Potamogeton hybridus, Michz. 
Common in stagnant water. 
Potamogeton lonchites, Tuckerman. 
Ipswich river. Merrimac river at Lawrence. 
Potamogeton pulcher, Tuckerman. 
Chebacco pond; Ipswich river; Beaver pond, Beverly; Crane pond, 
West Newbury. 
Potamogeton amplifolius, Tuckerman. 
Wenham pond, Ipswich river, ponds in Andover and Haverhill; fine 
fruit Aug. 19 (1879), Crane pond, West Newbury, river Parker, etc. 
Potamogeton gramineus, L. 
Wenham, and Pleasant ponds, Wenham. Quite abundant and vari- 
able. 
Var. heterophyllus, Fries. 
Georgetown (J. H. Sears), Sluice pond (C. E. Faxon). 
Potamogeton lucens, L. 
‘‘ Breed’s pond, Lynn” (Tracy). Recent search has failed to verify 
this determination; and specimens, which at first were supposed to 
be this species, proved to be imperfectly developed forms of P. 
amplifolius. 
Var. minor, Nolte. 
Pleasant pond, Wenham (J. R., etc.). Scarce. This will probably 
prove a good species, and as it is the same as the European P. 
Zizii, M. & K., it will be given under that name. 
Potamogeton prelongus, Wulfen. 
Wenham and Pleasant ponds, Wenham. 
Potamogeton perfoliatus, L. 
Ponds and streams. Frequent. 
~Potamogeton zosterefolius, Schumacher, Potamogeton com- 
pressus, Z. (Gray’s Manual). 
River Parker, West Newbury (J. R.); Lynnfield (Edwin Faxon). 
Rare. 
Potamogeton obtusifolius, Mertens & Koch. 
Pleasant pond, Wenham, Aug., 1875 (J. R.), 1880 (C. E. Faxon). 
Potamogeton pauciflorus, Pursh. 
Wenham pond; Flax pond, Lynn (Tracy), Boxford. 
