292 



RESEARCHES ON FUNGI 



The Heliotropism of the Asci and the Discharge of the Spores 

 in Aleuria vesiculosa. — When a fruit-body of Aleuria vesiculosa is 

 more or less hemispherical in shape, hke those shown in Fig. 137, 

 the hymenium is illuminated by daylight which comes to it from 

 above ; so that, in a fruit-body of the shape postulated, if the asci 



Fig. 139. — Aleuria vesiculosa [— Peziza vesiculosa). Semi -diagrammatic median 

 vertical section through a small, fully expanded fruit-body vvliich grew in tlie 

 open on dunged soil at Winnipeg, Canada. To show the lieliotropic curvatures 

 of the ends of tlie asci and the general directions in which the asci would dis- 

 charge their spores : a, dunged soil ; b, tlie receptacle or fruit-body flesh ; 

 c. the liymenium. Tlie asci are everywhere bent upwards toward the source 

 of the strongest daylight, and the arrows indicate the direction in which the 

 spores would be discharged. Magnification, (i. 



are heliotropic, they should all point upwards toward the fruit-body's 

 mouth. Whether or not the asci of a more or less hemispherical 

 fruit-body do actually point toward the fruit-body's mouth can be 

 determined : (1) by examining the hymenium in radial-longitudinal 

 sections ; (2) by examining the hymenium in surface view ; and 

 (3) by observing the direction of the discharge of the spores in the 

 air with the naked eye or in water with the help of the microscope. 



