THE MAJOR VEGETATION OF LAKE OKOBOJI 
ROBERT B. WYLIE 
The major vegetation of Lake Okoboji consists chiefly of sub- 
mersed seed plants. The algae are always in evidence and play 
an important part in the life of the lake since they are used as 
food by many lower animals, but with the exception of Char a 
they are seldom conspicuous and never large. 
The aquatic seed plants present a wide range in size, structure, 
and flowering habits, but with the exception of the duckweeds, 
(which are only visitors on the main lake), they are good sized 
plants, and some of them are very large. The botanist sees in these 
submersed Angiosperms a group of plants of special interest since 
they present a double set of adaptations. Each must in the past 
have gained high achievement as a land plant, and they subsequent- 
ly taking to the water, there has been superimposed another set of 
habits and structures especially related to the present environment. 
Most people realize in a general way at least that there must 
be some such relation between the animal and plant life of the lake 
as there is between these groups on land. The lake animals are 
dependent directly, or indirectly, upon the associated plants for 
food, excepting of course such food materials as are washed into 
or fall upon its waters. The water plant is eaten directly by 
some of the fish, but usually it is transmitted to some of the 
higher lake animals through a series of lower organisms who de- 
rive their food from the plants. So intimate is this relationship 
that the success or failure of one form influences in corresponding 
proportion the welfare of other organisms which seem remote 
and independent. 
The major vegetation also provides shelter, attachment, and 
breeding places, as well as food for the animals. All of which 
suggests that the life of a permanent fresh water lake, like 
Okoboji, presents a complex series of inter-relationships between 
the various forms that dwell in its waters. With this in view 
various studies carried out at the Iowa Lakeside Laboratory have 
been directed towards determining the number and kinds of or- 
ganisms in Lake Okoboji, and the establishment of values for the 
many partners in the life-program of its waters. There must 
