THE VEGETATION OF TWIN ISLAND. 
RUTH MARSHALL. 
This paper is an attempt to add a small contribution to the 
floristic survey of northwestern Wisconsin with a superficial 
study of zonation. The region studied was a small island in 
Lake Spooner, Washburn County, two and one-half miles from 
the village of Spooner. Field work was carried on during the 
months of July and August, 1906. This work consisted in 
the collection of specimens of all the seed plants and fern- 
worts growing upon the island, the determination of their 
distribution in formations, with quadrat and transect studies, 
and the keeping of some general records of physical conditions. 
The final identification of the species and the arrangement of 
the field notes Was completed during the following college year 
at the University of Nebraska. 
Lake Spooner is a narrow, irregularly shaped lake, about 
three miles long, extending diagonally from south-east to 
north-west, with a maximum width of over one mile; it is con¬ 
siderably narrowed in three places. It is fed by Mud Creek, 
at the south-east end, where the water is filled with vegetation. 
Yellow Liver, the outlet, starts from one side of the enlarged 
northwestern end where there is an old mill-dam. The dam is 
defective; this fact and the scarcity of rain in the middle of 
the summer caused a fall of about eighteen inches in the sur¬ 
face of the lake during the time that it was under observation. 
Lake Spooner finally drains into the St. Croix Liver. The 
greatest depth of the lake is about thirty feet. It is of glacial 
origin and its islands are drift. 
The country about the lake was once covered with extensive 
forests of white pine, now nearly all cut down. Here and 
