622 MINNESOTA BOTANICAL STUDIES. 



over two feet deep and while the opposite walls approached each 

 other below, the gap at the surface was in many cases eight inches 

 wide. The West section was an expanse of mud ridges entirely 

 bare of vegetation, and was at first too soft to admit of a man 

 passing over it ; the East section, however, having risen out of 

 shallower water and partly out of a marsh, exhibited specimens 

 of yellow pond lilies (Nymphea advena), cattails, water plan- 

 tain, and common rush lifted out of the water and struggling 

 under adverse conditions. 



In the early part of July, 1898, the East section looked already 

 green from the distance. The aquatic plants just mentioned 

 still lived, but showed the effects of changed conditions. The 

 leaves of Nymphea advena, for instance, were all very short- 

 petioled, and were below normal size, appeared more or less 

 brownish and the younger ones were rolled from both margins 

 inward and upward. On the other hand, the number of true 

 land plants growing vigorously was already bewildering and 

 although most of them were still too young for a reliable inden- 

 tification, the following were found in bloom about July 5, 1898 ;* 



1. White clover {Trifolium r opens]. 



2. Red clover (Trtfolmm pratense). 



3. Wild mustard (Brassica nigra]. 



4. Peppergrass sp. 



5. Mayweed (Anthemis cottild]. 



6. Crucifer sp. 



7. Black nightshade (Solatium nigruni). 



8. Mustard sp. 



9. Polygonum sp. 



10. Timothy grass (Phleum pratense]. 



11. Grass sp. 



12. Kentucky bluegrass {Poa pratensis), out of bloom. 



The southern part of this section was covered with a compact 

 layer of fine silt from the railroad embankment and on this firm 

 soil little else but young mosses were growing. Scattered over 

 the higher part of the whole section were young cottonwoods 

 and willows. 



The most interesting plants found, however, were the pro- 

 thallia of horsetails, probably of Equisehim arvense, as that 



* The botanical nomenclature of this paper follows the " Illustrated Flora " of 

 Britton and Brown. 



