ADJUSTMENTS OF FRUIT-BODIES 71 



in 45 minutes. After further practice in handling the material and 

 in making observations, I found a fruit-body which curved upwards 

 through a right angle in 17*5 minutes. It gave a distinct macro- 

 scopic reaction to the stimulus of gravity after 3 minutes' stimulation, 

 turned through an angle of 10 in the first 5 minutes, and through a 

 further angle of 80 in the next 12-5 minutes. The pileus, therefore, 

 was turned through almost a complete right angle with an angular 

 velocity greater than that of the minute hand of a clock. This 

 angular velocity is far greater than that known for any Phanerogam 

 or, indeed, any other plant when stimulated by gravity. For a stem 

 to turn upwards through a right angle several hours are usually 

 required, whereas, as we have seen, the stipe of Coprinus plicatiloides 

 can perform this movement in 17'5 minutes. The latent period for 

 roots the time required for the commencement of curvature after 

 continuous geotropic stimulation is, according to Moisescu, 1 who 

 experimented on Lupinus albus, Cucurbita, &c., at least 15 minutes 

 when one observes with the naked eye. On the other hand, the 

 stipe of the Coprinus made a distinct curvature in 3 minutes. The 

 remarkable rapidity of the geotropic reaction in the fungus is com- 

 parable with the reactions of tendrils to the stimulus of touch. 2 



Moisescu 3 states that with the microscope he could detect a 

 slight downward curvature of certain roots after one minute of 

 stimulation. In an experiment in which a fruit-body was tilted to an 

 angle of 45 and the stipe supported on a rest so as to prevent its 

 initial sagging from the weight of the pileus, a distinct upward 

 curvature was observed with a horizontal microscope of low magnifi- 

 cation in one and a half minutes. Probably further experiments 



1 Moisescu, " Kleine Mitteilung iiber die Anwendung des horizontalen Micro- 

 skopes zur Bestimmung der Reaktionszeit," Ber. d. deutschen bot. Gesell., Bd. XXIII., 

 1905, p. 366. 



2 The movements of very sensitive tendrils in certain species are even more 

 rapid than that observed for the stipe. Thus, after rubbing the inner side of a 

 tendril of a Cucumber and placing the rubbed surface in contact with a stick, I 

 observed that the tendril made a half-turn round its support in five minutes, a 

 whole turn in ten minutes, and one and a half turns in twenty minutes. The 

 temperature was 85 F. The mean angular velocity of the tendril for the first 

 ten minutes was 36 times greater than that of the stipe, although after twenty 

 minutes it had become only 5'5 times greater. 



3 Moisescu, loc. cit. 



