The place was not again visited until spring. In April, the 

 lumber pile having been removed, the place was made easy of 

 access and was again examined more thoroughh'. y\ll external 

 signs of the Phalli had disappeared, but the bed of sawdust was 

 found densely matted together with mycelium which covered 

 a space of several square feet and penetrated the sawdust to a 

 depth of 12 to 15 inches. Throughout the mass there was an 

 abundance of tubercles. They as well as the mycelial cords 

 were now observed to be white in color where not exposed, but 

 when uncovered quickly turned bluish-purple. This change of 

 color was very marked and always occurred first in the finer 

 threads of the mycelium where it would take place so quickly on 

 exposure that it was very difficult to catch sight of the natural 

 white color of the threads before the blue color appeared. For 

 this reason the mycelial threads of P. Ravcnclii are usually ob- 

 served to be bluish-purple in color. In a few seconds the blue color 

 would appear on the more exposed prominences of the tubercles, 

 rapidly deepening in color and spreading over the surface, but not 

 at first extending into the depressions between the prominences, 

 owing apparently to the retention of some moisture in these places. 

 The side of a large tubercle which remained in contact with the 

 moist sawdust also underwent no change. This suggested that 

 the change of color was due in some manner to a superficial dry- 

 ing resulting from contact with the air, which appeared to be 

 confirmed by the fact that if the tubercles of the mycelium were 

 immersed in w^ater as soon as removed from the sawdust not only 

 was further change of color checked, but after a few minutes the 

 color which had already appeared faded out and the material soon 

 became entirely white as at first. 



By very long exposure to the air, that is, for several hours or 

 days, the color gradually undergoes a further change, becoming 

 a dark reddish-brown and spreading over the entire surface even 

 into the deepest depressions, and this is more uniform and com- 

 plete in the living plant remaining in contact with its substratum 

 than when removed and dried. 



This color change in the tubercles is confined stricth' to a \ery 

 thin layer of the surface and does not penetrate the inner sub- 



