CORTINARIUS AS A MYCORHIZA-PRODUCING FUNGUS’ 
C. H. KAUFFMAN. 
(WITH ONE FIGURE) 
THE study of the mycorhiza problems has received a new impetus 
during the last six years by the appearance of extensive papers by 
MacDovueat (1), STAHL (2), TUBEUF (3), HILTNER (4), and MULLER 
(5). Considerable evidence has been adduced showing that in the 
case of the endotrophic mycorhiza the organisms concerned act as 
purveyors of nitrogen to the symbiont or host with whose roots they 
are connected (6-7); furthermore, the organisms in some of these 
cases have been quite exhaustively studied (8-9). On the other 
hand, the fungi which cause the ectotrophic mycorhiza have not 
been investigated except in a very few cases. 
It is a noticeable fact as one looks over the literature, that the 
larger part of the work hitherto attempted has been done on a basis 
of several unknown quantities. One of these is the identity of the 
fungus which causes the ectotrophic mycorhiza. The earlier writers 
speak of the fungus as if it were a single species or genus. It was 
thought for quite a time that the ectotrophic mycorhiza of European 
trees was due in all cases to the tubers or truffles. WORONIN (10), 10 
1885, showed that this cannot be true for Finland, where the tubers 
are not found, but where nevertheless the mycorhiza are abundant. 
KaMIENSKI(11) also found no truffles in the regions where he studied 
the mycorhiza of Monotropa. ReEEs (12) was at first inclined t0 
think that Elaphomyces was the cause of the mycorhiza of almost § 
the trees he examined; later, he himself found mycelium of mycorhiza 
which differed in structure from that of Elaphomyces. 
The fungi whose fruiting forms have been definitely reported 
as belonging to mycorhizal mycelium are comparatively few. Mac- 
DovuGaL (1) gives a list of mycorhizal fungi whose identity has 
been reported. The list is as follows: Fusisporium, Eurotium 
Pythium, Nectria, Celtidia, Elaphomyces, Geaster, Boletus, Tn- 
choloma, Lactarius, and Cortinarius. Of the non-mycelioid aie 
* Contribution 89 from the Botanical Department of the University of Michiga® 
’ Botanical Gazette, vol. 42] & 
