Wheeler: FLORA OF SOUTHEASTERN MINNESOTA. SDL 
low stages they may be left out of the water entirely and when 
the water is at its height most of them are nearly or quite sub- 
merged. The plants adapting themselves to these conditions 
might be considered as the Sagz/tarza group, for the two Sagzt- 
tarias—latifolia and r7g7da—are the most abundant shore plants 
with the possible exception of Eleocharis acicularis. Nelumbo 
lutea may often be seen in times of very low water, grow- 
ing on the muddy banks entirely emersed holding its leaves 
erect two or three feet above the mud, while the Castaléa when 
placed under these conditions lodges its leaves on the mud where 
they soon die. Polygonum emersum covers many banks to the 
exclusion of other vegetation. It is adapted to living on the 
exposed mud or in the water but under the latter conditions it 
always projects its leaf-bearing stems out of the water and keeps 
the foliage leaves emersed. 
WET MEADOWS OF THE RIVER VALLEY. 
During a large part of the growing season the wet meadows 
of the river bottoms are submerged. When they are exposed 
for a sufficient length of time to become somewhat dry the 
grasses are generally cut for hay. The plants living under 
these conditions are mostly coarse grasses and sedges. No trees 
but willows seem to be able to live upon these meadows and 
they do not then attain tree size. Some of the plants forming 
the vegetation of the wet meadows are: 
Asclepias tncarnata, Scirpus atrovirens, 
Cyperus esculentus, Scirpus cyperinus, 
Eleocharis acicularts, Szum cicutacfolium, 
Elymus virginicus, Sparganium eurycarpum, 
Eragrostis hypnordes, Spartina cynosurotdes, 
Eupatorium pur pureum, Vernonia fasciculata, 
flomatlocenchrus virginicus,  Zizania aquatica. 
Penthorum sedotdes, 
MupD-FLAT VEGETATION. 
The mud-flat comprises the highest land of the islands. It is 
flooded only during the early summer but on account of its 
growth of timber and shrubs the soil remains wet during the 
entire year. The largest trees growing anywhere in this region 
are found on the mud-flats of the Mississippi river. 
