368 Wisconsin Academy of Sciences, Arts, and Letters . 
dimidiate imbricated form is L. flabelliformis there and L. Ameri¬ 
canos here. 
5. The same is true also of the Lentinus lepideus group. An¬ 
nulate and exannulate forms are found in each country. Obconicus 
here resembles suffrutescens there, spretus here may be closely 
allied to homotinus there. Many monstrous forms are found in 
the group in both countries. 
6. In the Lentinus ursinus-vulpinus group, the corrugated 
scrupose forms (L. vulpinus), the even tomentose forms (L. ur- 
sinus), and the smaller, smoother forms (L. castoreus) are found in 
both countries. 
This great similarity between the species of Lentinus in North¬ 
eastern North America and Central Europe was to be expected 
from what is known of the relationship between the floras of the 
two regions in general. The cool temperate zone in the northern 
hemisphere is divided into an eastern and a western floral region 
in both the old world and the new, middle Europe and the China- 
Japan regions in the old world and the Great Lakes region and 
the Northwestern states in this continent. The floras of Europe 
and the Great Lakes region are very closely akin, the China-Japan 
region comes next while the flora of the Northwestern states is 
farthest removed. This is due to geological history even more 
than to climatic conditions. The Lentinus flora of Western Amer¬ 
ica is not well known, but according to the North American Flora 
the Lentinus lepideus group appears to be the only one of the 
groups found in the region of the Great Lakes which has repre¬ 
sentatives on the Pacific coast. It is found also in Asia. L. ti- 
grinus extends west to the Rocky Mountains, and the Lentinus 
cochleatus group has a single known representative, L. piceinus in 
Idaho. The other groups, so far as known, are confined to Europe 
and the eastern half of the United States and Canada in the cool 
temperate zone. 
In the warm temperate zone and in the tropics, species of Len¬ 
tinus become very abundant, but none of our forms appear to be 
found in those regions except tigrinus which extends as far south 
as Cuba and is reported also from Australia. Our knowledge of 
local floras is, however, too scanty to permit any definite statements 
as to the character and distribution of the Lentinus flora of the 
globe as a whole. 
Fries’ scheme for the division of the genera of tough and woody 
fungi into sections is based on the position of the stem or point of 
