[VoL. 3 
434 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
from our own results has certainly designated the Phoma 
group of organisms as worthy of further careful study. 
With respect to the accumulated data for Penicillium, 
Macrosporium, Alternaria, and other saprophytic moulds oc- 
curring in the soil or upon decaying vegetation, it can only be 
said that the data fall into the same category as that for 
Aspergillus niger. We do not take issue with those reporting 
fixation, but we feel that in view of strong negative evidence 
regarding many of these fungi, further assurance must be 
given that the results may not be explained on the ground of 
experimental errors. We are quite well aware that the ad- 
mission of the data for Phoma Betae has virtually thrown 
open the whole question for any and all fungi, yet we can find 
no grounds upon which adequately to criticize either our own 
results or those of Ternetz with another species of this genus. 
Accepting the evidence for certain species of Phoma, in what 
direction shall we seek for organisms similarly endowed? 
Naturally related genera among the Sphaeropsidales would 
first be suggested, on purely morphological grounds. Again, 
for a long time physiologists have seen possibilities in organ- 
isms which have undergone such adjustment as characterizes 
the mycorhizal fungi generally. Up to the present time there 
has existed considerable uncertainty concerning the isolation 
and determination of the species which produce mycorhiza. 
Ternetz alone has demonstrated a Phoma as a root organism 
of this type. Peklo’s studies lead him to believe that Penicil- 
lium and an undetermined fungus are involved. In this case, 
as already noted, a very weak nitrogen fixation was reported. 
It is not intended, however, in this connection to discuss the 
various indications respecting mycorhizal fungi. Attention 
may be drawn to the fact that the predominant presence of 
Basidiomycetes in forests and meadows early suggested the 
association of these forms with the roots of higher plants. In 
recent times species of Tricholoma, Lactarius, Cortinarius, 
and Boletus have been strongly suspected of being important 
in the development of mycorhiza. 
The fungi are the primary agencies whereby vegetation is 
usually disintegrated or brought through the first stages of 
