I30 



BOTANICAL GAZETTE 



[august 



{b\ A zone of 



extending nearly around the lake, 



occupying the territory between the preceding zone and the 

 water's edge. This forms a zone between thirty and seventy 

 feet In width, whose lakeward side is about six feet below the 

 surface of the water, while the shoreward side is limited by the 



Fig. 2. — North shore of the lake ; Nuphar, Carex, and Salix zones ; the shrubs in 

 the background are mostly Fopuius tremuloides, 



water's edge. The most abundant and characteristic plant in 

 this zone is Nuphar advena Ait. f. Its rapid growth and hardi- 

 ness make it a successful competitor in the struggle among 

 aquatic plants, and it is admirably adapted to the requirements 

 of an advancing plant society, growing as vigorously in water 



six feet deep 



[fig^ 



Associated 



with it are Potarnogeton natans L., P. luce?is L., Chara coronata Ziz., 

 Dulichiiim spathacetim Pers., and Typha latifolia L. 



In places where for any reason Nuphar does not grow or 

 grows only sparingly, Potarnogeton zosteraefoliiis comes in ; where 

 Nuphar grows well Potarnogeton is not found. 



