512 RESEARCHES ON FUNGI 



develop about the same time, but it often happens that one or two, 

 particularly those at the end, attain full size before their fellows (B). 

 As a rule, however, the slightly younger spores of a basidium become 

 full-sized before the slightly older ones are discharged (C). 



The passage of the yellow protoplasm from the basidial cells 

 into the basidiospores takes about an hour. Often from the clump 

 of protoplasm passing into the funnel-shaped sterigma bridles pass 

 to the walls of the cell concerned ; and one can also often detect 

 the presence of tiny particles on the cell-walls from which the 

 massive protoplasm has retired (D). These facts seem to indicate 

 that a lining layer of protoplasm is left in the cells until after the 

 discharge of the spores. There seems to me little doubt that not 

 only is this lining layer present but that it is also of distinct import- 

 ance in enabling the basidium to maintain its turgidity. 



In order to observe the discharge of a spore when magnified 

 about 450 times, it is necessary for one to concentrate one's atten- 

 tion on a spore which appears ripe, i.e. one which is of full size and 

 packed with the yellow protoplasm, and which has an associated 

 basidial cell emptied of massive contents (e.g. Fig. 206, C). After 

 waiting some minutes or the greater part of an hour, one may at 

 length see the event happen. Suddenly a drop of water begins to 

 be excreted from the hilum of the spore ; the drop quickly grows, 

 and, in the course of 15-25 seconds, attains nearly the same 

 diameter as that of the spore (F, a-c ; E). Then, in a flash, the 

 spore is shot out of sight together with its drop (F, d). The 

 sterigma is left vacant, but does not collapse : its end appears 

 closed, at any rate one cannot detect a hole in it or any sign of its 

 having been broken across. The spores are shot off one after the 

 other in succession in the course of several minutes or an hour ; 

 and, when all the spores have gone, the basidium collapses and dies. 

 There is practically only an empty shell of chitin left behind : the 

 living substance has all been sent away on four journeys through 

 the air. 



The distance to which the basidiospores can be shot from the 

 basidia in a horizontal direction in still air can be found without 

 much difficulty. In a preparation which has developed in a closed 

 Petri dish one first finds places where the aecidiospores lie far apart. 



