V 



THE SPHAEROBOLUS GUN 325 



referred to as a lubricating agent which prevents the projectile from 

 sticking to the gun and eases the separation of the projectile from 

 the gun at the moment when the inner set of membranes has attained 

 its maximum state of e version. By placing a sheet of glass in front 

 of discharging Sphaerobolus fruit-bodies I have been able to ascertain 

 that, when discharge takes place, some seven or eight drops of the 

 slimy liquid are shot away from the gun. These drops are much 

 smaller than the projectile and doubtless, under natural conditions, 

 are not shot nearly so far. 



The projectile lying in a stellately opened fruit-body just before 

 discharge is spherical in form. If a glass plate is placed about 

 2 inches in front of such a fruit-body, the projectile, on being 

 discharged, impinges upon it with great violence and flattens out 

 like a leaden bullet, thus becoming shallowly plano-convex. As 

 the projectile flattens out, its diameter increases from about 

 1-1 • 25 mm. to about 1 • 5-2 • 25 mm. 



The Sphaerobolus gun opens stellately, slowly and silently ; but, 

 when it discharges its projectile, it emits an audible sound. Also, 

 when a projectile impinges upon and flattens out against a solid 

 body such as a sheet of glass or the ceiling of a room, the sound of 

 the impact can be readily heard. Comparative observations 1 have 

 taught me that the Sphaerobolus gun is not only the largest and the 

 most powerful but also the loudest of all fungus guns. 



The Range of the Gun. — In 1920, at the time my investigations 

 on Sphaerobolus were begun, the horizontal distance and the vertical 

 height to which the Sphaerobolus gun is able to throw its projectile 

 had not been exactly measured. The horizontal distance of dis- 

 charge was said : by C. G. Lloyd 2 to be from one to five inches, 

 depending on the vigour of the plant ; by G. Massee 3 to be a foot 

 or more ; and by de Bary 4 and Zopf 5 to be a metre and upwards. 



1 Vide these Researches, in the forthcoming Volume VI. 



2 C. G. Lloyd, Mycological Notes, Cincinnati, U.S.A., No. 33, 1909, pp. 432-433. 



3 G. Massee, British Fungi, with a Chapter on Lichens, London, not dated, 

 1911 (?), p. 469. 



4 A. de Bary, Vergleichende Morphologie und Biologie der Pilze, Leipzig, 1884, 

 p. 353. In the English edition, de Bary's " metre " has unfortunately been trans- 

 lated as a " millimetre " ! Vide A. de Bary, Comparative Morphology and Biology 

 of the Fungi, Oxford, 1887, p. 328. 



5 W. Zopf, loc. cit., p. 375. 



