CHAPTER VI 



MACROSCOPIC OBSERVATIONS ON THE FALL OF SPORES OF 

 POLY FOR US SQUAMOSUS 



From the foregoing chapter it is clear that enormous numbers of 

 spores fall continuously during the spore-fall period of a large 

 hymenomycetous fruit - body. Nevertheless, the spores are so 

 minute that, as a rule, one cannot observe the spore-clouds with 

 the unaided eyes. If it were not for the exact investigation into 

 the matter, it would be difficult to believe, when one holds up a 

 large ripe Mushroom, that, before one's very eyes but yet unseen, 

 a million spores fall from the gills each minute. However, a 

 visible spore-discharge has occasionally been observed as a rare 

 phenomenon. Thus Hoffman 1 has recorded having seen spore- 

 clouds leaving the under surface of Polyporus destructor, whilst 

 Hammer 2 has more recently observed tiny wreaths of spores 

 ascending to a height of 2 or 3 feet from a fruit - body of 

 Pleurotus ostreatus placed upon a table. Hermann von Schrenk 3 

 states that from a fruit-body of Polyporus Schweinitzii, "the 

 spores came off at intervals as if they were being discharged 

 by some force acting within the tubes." It may be remarked 

 that, from numerous observations of my own made by the beam- 

 of-light and other methods 4 on various species of Polyporese, 

 there seems to me to be no doubt that the spores which von 

 Schrenk observed were falling continuously and regularly by their 

 own weight, and that the intermittent clouds were caused by 

 tiny, irregular air-currents which swept the spores along beneath 



1 Hoffman, Jahrb.fiir wiss. Bot, Bd. II., 1860. 



2 Hammer, "A Note on the Discharge of Spores of Pleurotus ostreatus," Torreya, 

 V., 1905, p. 140. 



3 H. von Schrenk, "Some Diseases of New England Conifers," Bull. 25, U.S. 

 Dep. of Agric, 1900, p. 22. 



4 Vide infra, Chap. VII. 



