1909] STREETER—-DIRECTION OF GROWTH OF AMANITA 421 
angle of 145° with the position from which it started. This shows 
that at least part of the responsive zone is very near the tip of the 
stipe. In other cases, where the stipe had nearly reached its greatest 
elongation, the result was the same (fig. rz). Here the stipe was 
Fic. 9 
Fic. 8 
Fic. 8. A. crenulata: a, entire; b, as planted, the pileus having been removed as 
indicated by the lines, dotted lines show depth of pileus; ¢, 24 hours later, showing 
that curvature takes place in stipe, not in pileus.—Fic. 9. A. crenulata: a, entire; b, as 
Planted, the pileus having been removed by transverse cut ab; ¢, 24 hours later, show- 
ing curvature of 124°. 
56™™ in length, of which r™™ projected beyond the end of the tube. 
+ . . . . mm 
In this case elongation continued until the stipe projected 3™™, and 
it then showed an upward curvature of 2 3°. In this case the respon- 
sive zone must have been within 1™™ of the tip at the start. 
In order to determine the distribution of the zone of elongation, 
