136 NEW YORK STATE MUSEUM 



NAIADACEAE 



POTAMOGETON 



Leaves of two kinds, submerged and floating 1 



Leaves all submerged ...., 4 



1 Submerged leaves filiform, bladeless 2 



1 Submerged leaves not bladeless 3 



2 Floating leaves an inch broad or more natans 



2 Floating leaves less than an inch broad Oakesiauus 



3 Submerged leaves linear, sessi le, two ranked Nuttallii 



3 Submerged leaves linear-lanceolate, tapering to a sessile base alpinus 



3 Submerged leaves broad, petiolate amplifolius 



4 Leaves ovate or lanceolate, less than 3 in. long perfoliatus 



3 Leaves elongated, more than 3 in. long praelongus 



r 

 Potamogeton natans L. 



Floating pondweed 



Shallow water. South end of Lake Placid. 



Potamogeton Oakesianus Robbins 



Oakes's pondweed 

 Shallow water. Mirror lake. Fruiting specimens not seen. 



Potamogeton Nuttallii C. &^ S. 



J-*. Pennsylvanicus Cham. 



Nuttall's pondweed 



A common species in some parts of the Adirondacks but rare in North 

 Elba. Lake Placid. 



Potamogeton alpinus BabMs 



P. rufesceiis Schrad. 



Northern pondweed 



South end of Cascade lake. July. This and the next species just 

 come within the town limits at this place. They were collected here 

 many years ago, but have not been noticed elsewhere. 



Potamogeton amplifolius Tuckm. 

 Large leaved pondweed 

 South end of Cascade lake. July. 



