Lake Maxinkuckee, Physical and Biological Survey 125 



While the division line between the lake flora and the land flora 

 is in most cases pretty sharply drawn, it is not so easy to tell where 

 the boundary line lies between the plants having some influence 

 upon the lake and those which have none, if there be any such. 



The forests upon the shores of the lake have a marked influence 

 in sheltering it from strong winds. As everywhere else, their 

 leaves break the impact of heavy rains, allowing the water to sink 

 gradually into the soil rather than run directly into the lake car- 

 rying their burden of soil with them. In this last mentioned func- 

 tion, indeed, forests some distance back from the lake exercise a 

 very important influence on the lake. It is known that the lake 

 derives its chief supply of water from springs and flowing wells, 

 the waters of which sink into the surface, no one knows just how 

 far from the lake. Everybody knows how the disappearance of 

 springs is associated with the removal of forests. Indeed, during 

 the time that the lake has been under observation there has been 

 a marked diminution in the force and volume of many of the flow- 

 ing wells, and some of the marshes, such as Green's marsh and the 

 Inlet marsh, which at the beginning of the investigations were 

 miry, quaking bogs, where one could walk only on tussocks, are 

 now comparatively solid ground and are, indeed, mown meadows. 

 This change is a consequence of the lowered water-table of the 

 whole general region, and has taken place in other parts of the 

 state to such an extent that where cattle once would mire there are 

 now fields of corn and alfalfa. 



The falling leaves from trees near the lake sink to the bottom 

 of the lake and may be dredged up at all depths. Their decay 

 forms a black mud, and, although on account of the large area of 

 the lake, they are not so great a factor as in some of the smaller 

 lakes, their amount and influence is considerable. In one feature 

 they are quite important. It is between the leaves, as they sink to 

 the bottom, that some of the plankton algse, especially Anabaena, 

 the most abundant, and when in excessive abundance, the most of- 

 fensive of all the plankton-scum plants, hibernate during the win- 

 ter. Even the humble grassy covering of the sand-hills about the 

 lake has a direct bearing upon the latter; for when these are de- 

 nuded of all vegetation, the sand drifts and blows ; during the year 

 a considerable quantity is blown into the lake. During the winter, 

 when there is no protecting snow, the ice is soon covered with a 

 film of sand. Even the meadows about the lake, with their grasses 

 and other plants, bear a relation to the lake, in that they furnish a 

 habitat for various insects, particularly grasshoppers, which in one 

 way or another enter into the menu of the fishes. As shown else- 



