‘Ig06} KAUFFMAN—A MYCORHIZA-PRODUCING FUNGUS 213 
no uncertainty. Some of the strands and the connected rootlets were 
fixed and imbedded, and sections were made to determine the more 
intimate relations of the two organs. When stained rather deeply 
by fuchsin and gentian-violet the connection could be easily made 
out. It is clearly a true ectotrophic mycorhiza. There is a close- 
lying layer of parallel hyphae which surrounds the rootlet, and,-in all 
but the youngest rootlets, branches of this layer penetrate the root 
and form a close intercellular tissue exactly as figured by FRANK (13). 
The cells of the root at this time seem to contain little protoplasm 
and occasionally hyphal threads are seen to cross the cells of the 
cortical layer farther in. In the youngest roots no intercellular 
tissue appears to be present. 
It would seem that there must be some close physiological rela- 
tion; FRANK indeed thought he had demonstrated it. At the present 
time, however, nothing definite is agreed upon. To attempt in 
Some measure to solve this question, experiments are now under way 
With the mycelium of the above-mentioned mushroom. One fact 
may have some bearing on the problem; the species of the genus 
Cortinarius develop relatively slowly. The writer has never been 
able to bring buttons into the house and develop them there, as is 
possible with Amanitas and Volvaria. For some reason they seem 
to have lost the vigor necessary to this end. It may be that the 
explanation of this is found in that a part of their food supply is cut 
off, and that the tree really supplies some of the necessaries for the 
full development of the sporophore. 
Let it not be supposed that all Cortinarii are mycorhiza-formers, 
at least normally. Cortinarius armillatus, for example, although 
very partial to Tsuga canadensis, is usually found among rotten 
logs or leaf-mold near this tree, and is probably a saprophyte; on 
the other hand, it has been found growing out of a cleft at the base of 
One of these hemlock trees. It seems quite likely, however, that a 
good many Cortinarii are in symbiotic connection in the manner of 
the one described in this paper. During several seasons’ observations, 
T have found C. squammulosus, C. bolaris, and C. cinnabarinus again 
and again in places which would indicate some relation to one kind 
of tree. C. cinnabarinus seems to prefer the oak, the other two the 
beech. Noack (12) has shown the connection of Cortinarius callisteus 
