74 iPostelsia 



thest out in the lake working shoreward one 

 meets first with a zonally arranged society of 



Myriophylliun spicatum -.-This zone varies in 

 width and is not continuous. Its usual depth is 

 from 1-3 meters. Frequently in certain places 

 of this society are found scattered plants of 

 Nymph ecu polysc pala. 



The next zone shoreward is formed by a Po- 

 tamogcton society. This is principally composed 

 of Potamogeton naldus and Potamogeton piisilhis. 



In some of tlie small bays or inlets along the 

 shore this zone attains a com])aratively large 

 width. Along ])rojccting ]K)ints on the other hand 

 it frequently narrows down very much and often 

 becomes discontinuous. Potamogeton natans is 

 bv far the largest element in this zone. 



Of a still more interrupted character is a 

 society that shoreward succeeds the one just 

 mentioned and which is built up principally of 

 Nymphaa polysepala. It develops typically in 

 the bays or behind projecting spits of land. As a 

 a rule the plant occurs in dense patches where 

 often the large heart shaped floating leaves crowd 

 so close together as nearly to obscure the surface 



