RUDIMENTS OF FRUIT-BODIES 103 



them actually grow up into mature fruit-bodies. The rudiments 

 which are destined to produce spore-bearing fruit-bodies usually 

 arise at or near the bottom of the culture-dish and are separated 

 from one another by intervals of a few inches. They draw to them- 

 selves the contents of the mycelium, each one in this respect having 

 its own sphere of influence ; and, apparently by this very simple 

 means, they cause the inhibition of growth of the remaining much 

 more numerous rudiments, so that the latter soon cease their 

 development, wither, and die.^ Perhaps these aborted rudiments, 

 which at the best usually do not exceed a length of about 3 mm., 

 give up their contents to their more fortunate companions, but 

 the value of this suggestion can be decided only by exact 

 investigation. 



We have seen that of the numerous rudiments which begin their 

 development only a small fraction ultimately give rise to mature 

 fruit-bodies. What biological significance may be ascribed to this 

 fact ? We can here give an answer similar to that which was given 

 when a like question arose in regard to the supernumerary rudiments 

 of the Mushroom. 2 The mycelium produces numerous rudiments 

 at the surface of its substratum ; but only those develop which are 

 in the most favourable positions in respect to the mycelium as a 

 whole and to certain external conditions. The more rudiments 

 there are, the more likely it is that some of them will have originated 

 in positions highly favourable for further growth ; and these few 

 alone complete their development. The supernumerary rudiments, 

 which have all originated in the less favourable places, represent 

 the margin of safety required to secure success in reproduction. 

 The fungus, as it were, proceeds by the method of trial and error : 

 the rudiments which become aborted represent the errors, while 

 those which develop into spore-bearing fruit-bodies represent the 



1 Jacques Loeb {Regeneration, New York, 1924) gives a similar explanation for 

 the growth of certain groups of bud-anlagen rather than others, on a leaf of Bryo- 

 phyllum calydnum. According to him, the inhibitory action of the growth of one 

 group of bud-anlagen on other neighbouring groups is due (1) to the fact that sap 

 and nutrients flow to the group that begins growth first, and (2) to the fact that the 

 continuation of the flow to the growing organs prevents the bud-anlagen in other 

 groups from obtaining the sap and nutrients necessary to initiate their growth. 



2 Cf. these Researches, vol. ii, 1922, pp. 398-399. 



