THE SPOKE-FALL PERIOD 103 



tory. Moisture was supplied to each fruit-body by means of wet 

 cotton wool placed on the upper surface. 



An apparently full-sized fruit-body of Schizopltyllum commune, 

 less than a square inch in area, shed its spores for sixteen days 

 continuously. The density of the spore-stream leaving the gills 

 seemed to remain almost constant from a few hours after its 

 formation onwards, until about three days before the end of the 

 spore-fall period, when it began to grow distinctly feebler. 



A small fruit-body of Polystictus versicolor shed spores for 

 sixteen days, and one of P. hirsutus for five days. A large 

 specimen of Lenzites betulina gave a copious shower for ten days. 

 A number of other fruit-bodies, such as those of Stereum hirsutum, 

 S. purpureum, Dzedalea unicolor, Merulius coriuni, &c, were seen 

 to discharge their spores for several days. A complete investi- 

 gation into the spore-fall period in all these species, doubtless, 

 would add much to its length. In order to carry it out, it would 

 be necessary to examine a fruit-body growing upon its substratum 

 from the time it begins to develop its hymenium onwards. It 

 has already been found that a very young fruit-body of Polystictus 

 hirsutus, grown in the laboratory on a stick, began to shed a few 

 spores when its hymenial tubes had only attained the size of 

 hemispherical depressions. From this observation, and also from 

 the fact that both small and large fruit-bodies of Schizophyllum, 

 Lenzites, Polystictus, &c, liberate spores when kept moist, it seems 

 probable that spore-fall takes place in species belonging to these 

 genera in a manner similar to that exhibited by Polyporus squamosus, 

 I.e. the discharge of spores begins soon after the fruit-bodies have 

 expanded horizontally, when the hymenium begins its development, 

 and continues until the pilei have grown to their full extent. This 

 may be in some cases a matter of days, in others certainly of weeks, 

 or in yet others possibly of months. 



For Pscdliota campestris and allied fruit-bodies spore-fall does 

 not begin until the pileus has expanded and the gills have become 

 more or less horizontally outstretched. By placing paper close 

 beneath the pilei of some Mushrooms growing on an artificial bed, 

 and thus collecting the spores, it was found that the spore-fall 

 period continued for two or three days. 



