326 RESEARCHES ON FUNGI 



to be 18 feet 7 inches ; and its maximum vertical range, as measured 

 by Leva B. Walker, was found to be 14 feet 5 inches. For Sphaero- 

 holus stellatus var. giganteus and for S. iowensis Miss Walker found 

 the maximum vertical range of the projectiles to be about 11 feet 

 and about 12 feet respectively. ^ 



The sound of the discharge of the Sphaerobolus gun is quite 

 distinct and has long been known. It was heard by E. Fischer ^ in 

 1884 ; and it was mentioned by de Bary ^ in 1884 and by Zopf * in 

 1890. I heard it as a little snap when the gun was a foot in front 

 of my eyes.5 Of all fungus guns the Sphaerobolus gun is not only 

 the largest and most powerful, but also the loudest. Its sound is 

 much louder than that of the ascus of Peziza and appreciably louder 

 than that of the sporangiophore of Pilobolus. 



The projectiles cf Sphaerobolus are shot away with considerable 

 speed and, as they are of the size of very small shot, it is not sur- 

 prising that, when they strike a hard object near their place of 

 discharge, the impacts are audible. These impact-sounds were 

 remarked by Micheli ^ in 1729 and have been noticed by a number 

 of observers since. Some thirty years ago I had some Sphaerobolus 

 fruit-bodies in a covered glass dish, and I remember very well 

 hearing the impact of the glebae as they struck the glass cover and 

 flattened out upon it. The sound of a glebal projectile striking 

 against glass in this way is distinctly louder than the sound of the 

 discharge of the gun which fires the projectile. 



Type II : Pilobolus. — The sporangium of the larger species of 

 Pilobolus (Fig. 27, p. 69) and the sap of the subsporangial swelling 

 which travels with it make up a projectile (Fig. 74, p. 151) which 

 is nearly spherical and about 0-6 mm. in diameter. The projectile 

 can be fired upwards from the sporangiophore a distance of 3-6 feet 

 and horizontally 4-8 feet.'^ As with Sphaerobolus, two sounds can 



1 These Researches, Vol. V, 1933, pp. 325-335. 



2 E. Fischer, " Entwickhxngsgeschichte der Gastromyceten," Bot. Zeit., 1884, 

 Nos. 28-31. 



^ A. de Bary, Vergleichende Morphologie und Biologie derPihe, Leipzig, 1884, p. 353. 



^ W. Zopf, Die Pilze, Breslau, 1890, p. 375. 



^ These Researches, Vol. V, 1933, pp. 325 and 326. 



^ P. A. Micheli, Nova Plantarum Genera, Florentiae, 1729, p. 221. 



' Vide supra, pp. 66-68. 



