ADJUSTMENTS OF FRUIT-BODIES 



73 



oscillation was therefore about one-third of the previous swing up 

 to the normal position. Each succeeding oscillation was made in 

 less time than its predecessor, and the whole series of movements 

 was completed in an hour and a quarter. In making observations 

 upon the amount of curvature, advantage was taken of the fact 

 that the plane of the base of the pileus, viewed horizontally, appears 

 as a straight line (cf. Fig. 27). The tilt of this line was measured 

 by placing a sliding lever parallel to it, and then reading off the 



FIG. 28. Eesults of observations on the movements of a fruit-body of Coprinus plicati- 

 loidcs about its normal position in response to the stimulus of gravity. The fruit- 

 body at the beginning of the experiment was turned from a vertical in to a horizontal 

 position. The ordinate gives the inclination of the axis of the end of the stipe to 

 the vertical in degrees and the abscissa the time in minutes. The curve drawn 

 through the observation points shows that the fruit-body executed a series of 

 damped oscillations. 



deflection from a horizontal plane by means of a surveyor's pro- 

 tractor. Since the axis of the end of the stipe is always perpen- 

 dicular to the plane of the base of the pileus, the divergence of 

 the latter from the horizontal gives the divergence of the former 

 from the perpendicular. The fruit-bodies, attached to their horse- 

 dung balls, were kept in a covered glass vessel in order to prevent 

 loss of moisture. The laboratory temperature was 20 C. The 

 deflections of the stipe from the vertical at successive periods of 



