310 RESEARCHES ON FUNGI 



sterigma. My observations therefore seem to warrant the conclu- 

 sion that the excretion of a water-drop is in some way absolutely 

 necessary for the discharge of the spores in Hymenomycetes. 

 Non-excretion and excessive excretion of water at the sterigmatic 

 neck appear to be equally fatal to the spores concerned : both 

 lead to the turning of normal-looking spores into wasters. In 

 Panaeolus campanulatus I believe that the formation of many of 

 the wasters is connected with the non-excretion of the water-drop. 

 Some of the waste spores, as judged by their size or colour or 

 both, are evidently very immature (Fig. 103, a, b, c, d, e, p. 306). 

 For some reason or other their development proceeded to a certain 

 point only and was then inhibited. One could hardly expect such 

 unripe spores to be shot away, for probably the development of 

 the mechanism of discharge is connected with the final stages 

 of ripening of the spores. 



Among the waste spores one often finds some which are unusually 

 large or unusually small or misshapen (Fig. 103, /, g, h). Clearly 

 these are abnormal spores. The forces which cause a spore to 

 become monstrous may also interfere with the discharging 

 mechanism. 



Sometimes one finds a little heap of wasted spores. In such 

 a case it would seem that several adjacent basidia have failed in 

 spore-discharge, and have each contributed spores to the heap. 

 The spores of two basidia belonging to two successive generations 

 may become stuck together so as to form a little group of eight. 

 Smaller or larger groups of wasted spores may be formed by slight 

 variations of this process. 



Significance of the Protuberancy of Mature Basidia. It has 

 been pointed out that a basidium, when beginning to get ready 

 to produce spores, grows in length until it protrudes a certain 

 distance above the general level of the hymenial surface. The 

 amount of the protuberancy thus attained will be at once realised 

 by reference to Fig. 96 (p. 287). After the basidium-body has 

 reached its full length, then, and then only, are the sterigmata 

 developed ; and only when the sterigmata have been pushed out 

 to their full extent do the spores begin developing at their ends. 

 The phenomenon of protuberancy, as will be shown in detail 



