Bergman and Stallard: climax formations ?)i^ 



Eqiiisctum flitviatile often occurs as a socles in this associes. It 

 seems to thrive best on a silty bottom in a depth of one to three feet 

 of water. In places it forms rather extensive areas of pure growth, 

 notably on Leech Lake near the mouth of Boy River and at the 

 west end of Long Lake near Ely. Usually, however, Equisetum 

 occurs mixed with other species of the associes. 



The distribution of the consocies depends upon the character of 

 the lake shore. Scirpus is able to establish itself in well-packed 

 sand or sandy gravel, and where the lake shore is of this character, 

 Scirpus is usually or often the only species present. It may become 

 established on a lake shore and extend out to a depth of six or eight 

 feet of water without being preceded by the Chara-Philotria and 

 Cast all a-Nynnphaea associes of the normal succession. Lake shores 

 of pure, packed sand occur where the shore is subject to heavy 

 wave-action or to a limited amount of ice-action. On shores much 

 exposed to wind-driven ice, the force with which the ice masses 

 are carried is sufficient to plow up the shore, completely preventing 

 the establishment of Scirpus or other plants and often forming an 

 abrupt wall or bank along the shore exposed. 



Zisania is able to establish itself only where the shore or bottom 

 of a lake or river is covered with silt or with a considerable amount 

 of decayed plant remains, and consequently is not found in parts 

 of lakes subject to much wave-action or to the action of wind-driven 

 ice. This is true also of Phragmites and Typha, but apparently 

 Phragmites may become established where Zisania can not, either 

 because of the bottom or because of too much wave-action. 



Phragmites may be the first invader in a lake, but usually not 

 beyond a depth of two or three feet. Examples of this are to be 

 found along the south and west shores of Ball Club Lake and on 

 the west side of Little Winnebegoshish, and the Mississippi River 

 for a short distance above where it flows into Little Winnebegoshish. 

 It also occurs in abundance in Lake of the Woods from the mouth 

 of Rainy River to Oak Point, where it grows in five feet of water, 

 the maximum depth observed. 



Secondary species : Various duckweeds are to be found floating 

 on the surface, and as submerged plants different kinds of algae, as 

 well as Potamogeton, Myriophyllum, Utricularia, Batrachium, etc., 

 occur. The characteristic secondary species of this associes are the 

 following : 



