1909] STREETER—DIRECTION OF GROWTH OF AMANITA 415 
stipe horizontal, at an accurately measured distance, before a sheet 
of paper firmly supported on a vertical drawing-board. In front 
of the toadstool and always at the same distance from it as the paper 
was fixed a black screen having a pinhole aperture. The drawing 
was made by looking through the opening and tracing the outline 
of the plant as it appeared against the paper. Other records were 
made in this way from time to time, depending upon the object of the 
experiment. The plant was in no way disturbed, and these records 
showed all changes of position in the vertical plane, and from them it 
mas possible to measure these changes in units of angular measure- 
ments. : 
fo Fic..2 
Fic. 1 
M Fic. 1.4. crenulata, 11° from perpendicular.—Fic. 2. A. crenulata, 8°5 from 
perpendicular. __ 
A few simple experiments showed that the forms used were 
positively heliotropic. Specimens planted in tumblers were placed 
in boxes which were painted black on the inside.” One entire side of 
each box was left open and the boxes were placed in a west window 
‘with the exposed side toward the light. After standing in this 
position for 24 hours, the plants had bent 8° to 12° toward the light 
(figs. 1,2). In fig. 1 the main axis of the toadstool is shown inclined 
11° from perpendicular, and in fig. 2, 8°5. To avoid light stimulus, 
all experiments with reference to geotropism were performed within 
a moist dark chamber, which in turn was kept in a dark room. 
_ After the pileus broke through the volva, it took the stipe about 
24 hours to attain its full length in A. crenulata, and nearly 36 hours 
‘in A. phalloides. With a few exceptions this time element was con- 
