Bickett—The Larger Aquatic Plants of Green Lake. 391 
the sample came. The sample was converted to grams per meter, 
and this value multiplied by the length of the strip to give the 
total weight. The details of the data on these scattered plants are 
presented in table 7. 
The areas of the dilferent zones were measured on the map by 
means of a planimeter; these figures being checked up with data 
obtained by the Survey at other times. By multiplying the aver¬ 
age weights of species (table 6) by the appropriate area, the total 
weight of each species in each zone was determined. These figures, 
together with those for the scattered plants (table 7) are shown in 
tables 8, 9, and 10. Total weights of the species for the whole lake 
flora were obtained by adding together the values for the three 
zones. These are given in table 11. In each case the total weight 
of a species is expressed also as a percentage of the total weight of 
all plants in the zone under consideration. 
From tables 8, 9, and 10, table 12 was prepared. It shows the 
relative amounts of each species found at each depth, expressed as 
a percentage of the total weight of the species. 
Table 13 summarizes the results shown in tables 6 and 11 and 
shows the average yield for each zone and for the lake as a whole, 
expressed in various units. The averages for the separate zones 
are the same as those in table 6, and hence disregard the weights 
of the scattered plants. The latter, however, are included in the 
average for the lake as a whole. 
Quantitative Eesults 
The 309 samples, when divided into their species, gave 1,380 sub¬ 
samples. This is an average of 4.5 species per sample,—^which is 
nearly equivalent to 4.5 species per square meter. The correspond¬ 
ing value in Lake Mendota is only 3.5. Samples containing as^ 
many as twelve species were not uncommon in Green Lake, but a 
large number consisted of only one or two species. 
The average yield of Green Lake is much smaller than that 
found for Mendota. Whether this would hold all seasons is, of 
course, unknown. The area of the plant zone is also less than that 
of Mendota, the total yield being, therefore, very much smaller 
in Green Lake. 
The greatest difference between the two lakes is in the shallow 
water flora. In Green Lake Zone 1 is only a little more than one- 
third the area of that in Mendota. Its yield per unit area is less 
than one-third. The total yield is, therefore, very much less. 
