BllA 



RESEARCHES ON FUNGI 



early in May and continues without inter- 

 ruption until the first heavy frost in late 

 October or early November, when it suddenly 

 ends. During this period of approximately 

 six months, the liberation of the spores 

 never ceases and is remarkably uniform (cf. 

 Fig. 48). For the first few days after the 

 commencement of spore- fall, the spore-deposit 

 on the slides is rather scanty, but even 

 then can be seen with the naked eye. Soon, 

 however, the daily spore-deposit becomes 

 almost constant ; and it remains so for the 

 rest of the spore-fall season. Any increase 

 that may be observed is in the months of 

 July and August. 1 



The daily slide collections for two seasons 

 showed invariably their brown coating of 

 spores. Changing slides at regular intervals 

 throughout the day, and even throughout the 

 night, gave no indication of any periodicity 

 of discharge : the liberation of the spores 

 continued steadily throughout the spore-fall 

 period. On a still day White saw, just as 

 I did for Polyporus squamosus? the spores 



FIG. 49. Fomes applanatus. Diagram to show the 

 mode of escape of the spores from the hymenial 

 tubes. A, vertical section through four tubes of 

 a fruit-body attached to a tree. The tubes have 

 grown directly toward the centre of the earth so 

 that the long axis of each is perpendicular. In 

 each tube the spores are shot from the hymenium 

 into the centre of the cavity and then fall down 

 vertically in still air until they emerge from the 

 pore. The trajectories of a few spores are shown 

 by the arrows. B, a similar tube represented as 

 tilted through an angle of 1. As shown by the 

 arrows at a and 6, all the spores discharged above 

 c, i.e. in the upper five-sixths of the tube, hit and 

 stick to the tube's side, and are lost. Only at 

 and below c can the spores escape freely. C, a cross- 

 section through a hymenial tube-layer. 



1 J. H. White, loc. cit., p. 140. 



2 Researches on Fungi, vol. i, 1909, p. 90. 



