26 RESEARCHES ON FUNGI 



spore-deposits to sunlight resulted in a marked diminution in the 

 proportion of germinating spores. This series of experiments, 

 together with three others, has led me to the conclusion that, when 

 dried spores of Schizophyllum commune are exposed to direct 

 sunlight for a few hours, a certain proportion of them are rendered 

 incapable of germination, whilst those which germinate do so more 

 slowly than dried spores kept in darkness. Subsequent experiments 

 showed that the spores of Dxdalea unicolor are affected by sunlight 

 in the same manner as those of Schizophyllum commune. From 

 the point of view of spore-dispersion, the experiments seem to 

 indicate that the spores of these fungi, when drifting about in the 

 air, may survive exposure to sunlight for a whole day, and 

 that they may subsequently germinate, although with diminished 

 vitality. 1 



1 The injurious effect of sunlight upon the development of pathogenic bacteria 

 is now well known. In the case of fungi, Elving has shown that the spores of 

 Aspergillus ylaucus, and Laurent that those of Ustilago carbo, are killed by long 

 exposure to sunlight. Pfeffer's Physiology of Plants, English translation, vol. ii. 

 p. 247. 



NOTE. Since this chapter was set up, W. B. Grove has called my attention 

 to the fact that he has recorded (The Flora of Warwickshire, Fungi, 1891, 

 p. 419) the occurrence of a fruit-body of Stropharia semiylobata with the gills 

 white owing to the non-development of the spores, but otherwise perfect. 



