360 MINNESOTA BOTANICAL STUDIES. 



extend for some distance up the narrow dark ravines. In places 

 where timber covers the flooded areas the vegetation is similar 

 to that of the mud flat on the islands near the river. The vege- 

 tation of the open table lands I have called mesophytic field. 



Cold spring vegetation. 



The valleys of Winnebago and Crooked creeks have a great 

 many springs arising from the bases of the bluffs throughout 

 their whole length but perhaps more numerous at the heads of 

 the creeks than elsewhere. Some of the springs that outlet in 

 low level land occasionally form small cold bogs in which the 

 ordinary cold water plants find very favorable conditions for 

 growth. A large spring near the head of Clear creek, a short 

 branch of Crooked creek contains the greatest abundance of 

 typical cold water plants of any spring visited. The large 

 creeks do not contain much vegetation. The smaller creeks 

 often contain plants similar to those of the cold springs. 



The plants characteristic of cold running water are : 



Batrachiwn divaricatum, Mhnulus jamcsii, 



Batrachiuin tricho^hyllum^ Philotria canadensis ^ 



Bcrtila C7'ccta, Rori^a nasttirtium, 



Cai'dajuine hidhosa^ Veronica americana. 



JEpilobiums — colorattun and adenocaiilon — are often found 

 growing in cold spring water but are not peculiar to this local- 

 ity as they are also found growing in moist soil. None of the 

 spring plants can be called common to large areas, for the con- 

 ditions necessary for their growth are limited in extent. ( 



Pond vegetation. | 



There are but ver}' few natural ponds along the creeks. The 

 ponds are generally artificial and as such present a variety of 

 conditions and a corresponding variety of plants. A small 

 natural pond in a bog near Crooked creek contains all it can 

 hold of the yellow pond-lily. (Plate XXVII., B.) This is the 

 only place in which any of the water-lily famil}^ were found 

 outside of the sloughs and lakes of the Mississippi river. 1 



Wet meadow vegetation of the creek valleys. 



The wet meadows naturally cover a very large part of the 

 creek valleys but under present conditions most of them are 



