GENERAL SUMMARY 467 



and communicated to and recorded by the author, prove that apothecia 

 of Aleuria vesiculosa, growing under purely natural conditions and un- 

 touched by man, may puff intermittently. 



In respect to the heliotropism of their asci the cup-shaped apothecium 

 of Galactinia hadia resembles that of Aleuria vesiculosa. The asci on the 

 sides of an apothecium of G. hadia discharge their spores, not in directions 

 which are perpendicular to the hymenium, but obliquely upwards at an 

 angle of about 45°. 



Each hymenium-lined alveolus of a fruit-body of a Morchella or 

 Mitrophora is comparable with the single hymenium-lined cavity of one 

 of the cupulate Pezizeae. 



Investigations on fruit-bodies of Morchella conica and M. crassipes 

 have shown that the asci in each alveolus are curved toward the mouth 

 of the alveolus, and it is therefore concluded that the asci, hke those of 

 the Pezizeae, are heliotropic. 



Since, in a fruit-body of a Morchella, the asci in each alveolus point 

 toward the mouth of the alveolus and since the operculum of each ascus 

 is situated symmetrically at the end of each ascus, it is clear that, when 

 spore-discharge takes place, the spores must be shot through the mouths 

 of the alveoli into the open air. 



The folds or walls on a pileus in the Morchellaceae have been compared 

 with the gills on a pileus in the Agaricaceae. The ascus, as a gun, has 

 profoundly influenced the structure of discomycetous fruit-bodies ; and 

 the basidium as a gun has profoundly influenced the structure of hymeno- 

 mycetous fruit-bodies. 



In the Helvellaceae, more particularly in Ptychoverpa bohemica, 

 evidence indicating that the asci are heliotropic has been obtained. 



The asci of the Discomycetes and the basidia of the Hymenomycetes 

 are structurally and physiologically two very different types of fungus 

 guns. Whereas the asci are positively heliotropic, the basidia are an- 

 heHotropic. In the Discomycetes the positive heliotropism of the asci 

 is advantageous for spore-dispersal, whereas in the Hymenomycetes a 

 positive heliotropism of the basidia, if it occurred, would be disadvan- 

 tageous for spore-dispersal. 



Chapter III.— Various projectiles of fungi in order of size have been 

 listed. 



A Sphaerobolus gun gives out a distinct sound as it shoots away its 

 gleba ; and, when a gleba strikes a hard object near its place of discharge, 

 the impact is audible. Of all fungus guns the Sphaerobolus gun is not 

 only the largest and most powerful, but also the loudest. 



When a Pilobolus gun is discharged, just as in Sphaerobolus, two 

 sounds can be heard : (1) the sound of the exploding gun, and (2) the 

 sound of the projectile striking some object. 



A hissing sound emitted by the fruit-bodies of certain Discomycetes 

 when puffing takes place has been noticed, among others, by Desmazieres 



