SPORE DISCHARGE AMONG BAS1DIOMYCETES 



195 



loss of turgor of the basidium which can be recognized by change 

 in shape and size is shown by Buller's observations on a rather 

 large number of species. He found in all cases that the spores 



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Fig. 33. Diagrams of apparatus and materials used by Buller to secure 

 evidence of forcible discharge of basidiospores by Hymenomycetes. A. 

 Threads in ocular of microscope. B. Section of pileus to be mounted in 

 compressor cell; C, shown in sectional view. D. Compressor cell in 

 vertical position as seen through a horizonally placed microscope. There 

 is a bit of pileus near the top of the cell, moist paper at either side, and 

 water at the bottom. E. Basidium as seen with such a horizonal microscope, 

 one spore discharged. F. Diagram showing paths of discharged basidiospores 

 (indicated by arrows) and the necessity of vertical arrangement of gills if 

 spores are to fall unimpeded. G. Stages in basidiospore discharge as seen 

 when viewed from hymenial surface. (After Buller.) 



are violently discharged from the basidium in succession. More- 

 over, just before each spore is expelled, a drop of liquid exudes 

 at the hilum. During a period of a few seconds this drop increases 



