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 ((Vymphea 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 Vymphea 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 (Z77zfolium repens). 
Red clover ( 77zfolium pratense). 
Wild mustard (Brassica nigra). 
Peppergrass sp. 
Mayweed (Anthems cotula). 
Crucifer sp. 
Black nightshade (Solanum nigrum). 
Mustard sp. 
9g. Polygonum sp. 
10. Timothy grass (Phleum pratense). 
it.) 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 Aguzsetum arvense, as that 
oOnTr Ama Ww WN 
* The botanical nomenclature of this paper follows the ‘‘ Illustrated Flora ” of 
Britton and Brown. 
