360 RESEARCHES ON FUNGI 



and the Hymenomycetes, but they trace out in the air a more or 

 less parabolic trajectory and, within about one second of the moment 

 of leaving their guns, fall upon the ground. 



The projectiles of Pilobolus are shot horizontally a distance of 

 less than 9 feet, those of Ascobolus immersus a distance of less than 

 2 feet, and those of Sphaerobolus a distance of less than 20 feet. 



The projectile of Pilobolus consists of a sporangium containing 

 tens of thousands of spores and of a large adherent drop of cell-sap 

 derived from the sporangiophore (Fig. 172, a) ; that of Ascobolus 

 immersus consists of eight very large coherent ascospores with thick 

 gelatinous walls, together with an enveloping drop of ascus cell- 

 sap (b) ; while that of Sphaerobolus is a glebal mass consisting of 

 a gleba containing many thousands of basidiospores, gemmae, and 

 rounded cells embedded in a solid fatty matrix, the whole surrounded 

 on the exterior by a covering of cells derived from the innermost 

 layer of the peridium (c). From the point of view of comparative 

 morphology, therefore, the projectiles of the three fungi under dis- 

 cussion differ very considerably from one another. 



(2) Great Violence in the Discharge of the Projectile. As compared 

 with other fungi, the violence of discharge of the projectile in Pilo- 

 bolus, Ascobolus immersus, and Sphaerobolus is very great. Pilo- 

 bolus longipes and P. Kleinii can shoot their sporangia to a height 

 just exceeding 6 feet and horizontally to a distance of about 8 • 5 feet 1 ; 

 Ascobolus immersus can shoot its spore-mass to a height of 1 foot 

 2 inches and, doubtless, horizontally to a distance of 1-2 feet 2 ; 

 while Sphaerobolus stellatus can shoot its glebal mass to a height of 

 14-5 feet and horizontally to a distance of 18-5 feet. 3 In the 



In A. immersus, as already described and illustrated in these Researches (loc. cit.), the 

 eight spores of each ascus are relatively very large and are bound together by their 

 thick outer gelatinous cell-walls so that, together with the drop of ascus-sap which 

 surrounds them, they form a relatively very large projectile — too massive for the 

 wind to carry away. A. immersus, therefore, in respect to the nature of its projectile, 

 while resembling the species of Saccobolus, stands in striking contrast with most 

 other Ascoboli. 



1 Vide these Researches, in the forthcoming Volume VI. 



2 These Researches, Vol. I, 1909, p. 253. The maximum height of projection 

 measured was 35 cm. and the maximum horizontal distance measured was 30 cm. 

 With further experiment, the latter distance no doubt could be considerably 

 increased. 



3 Vide supra, p. 335. 



