320 RESEARCHES ON FUNGI 



As shown by data embodied in a comparative Table ^ in Volume I, 

 the spores of the Discomycetes and of the Agaricaceae and 

 Polyporaceae are of the same order of size, and they therefore have 

 about an equal chance of being dispersed by the wind when they 

 come within its sweep. In the Agaricaceae and Polyporaceae, the 

 spores, after discharge, fall down between the gills or down the 

 hymenial tubes and thus leave the fruit-body ; but, as if to facilitate 

 the spores being carried off by the wind, the pilei which produce 

 them are usually raised up on stipes or project laterally from tree- 

 trunks, etc., a free subpilear space for the passage of the wind and 

 the removal of the escaping spores thus being provided. In the 

 Discomycetes, where the asci look upwards, as in the Pezizaceae, 

 or more or less upwards or laterally, as in the Morchellaceae, the 

 chances that the wind will carry off the spores are enhanced : 

 (1) by the considerable range of the individual ascus guns ; (2) in 

 Pezizaceae, etc., by the simultaneous discharge of many of the 

 guns — the phenomenon known as puffing ^ ; and (3), in many species 

 of Pezizaceae and in all the Morchellaceae and Helvellaceae, by the 

 raising of the pilei above the surface of the ground by means of 

 stipes comparable with those of the Agaricaceae and Polyporaceae. 



It is characteristic of the Morchellaceae and many Helvellaceae 

 that the fruit-bodies appear in the spring, from March to May, 

 i.e. at a period of the year when the night temperatures are relatively 

 low. Falck's observations in the laboratory have led him to 

 suppose that, in a Morchella or Gyromitra growing under natural 

 conditions : (1) at night and during the day when the sky is over- 

 cast and the temperature is low, ripe asci accumulate in the fruit- 

 bodies but no spores are discharged ; (2) the discharge of spores 

 takes place only in the daytime when the fruit-bodies are warmed 

 by the sun ; and (3), in bright sunshine lasting for some hours, the 

 fruit-bodies discharge their spores continuously, i.e. in the order in 

 which the asci ripen and not in intermittent clouds.^ Thus, according 

 to Falck, normal spore-discharge in a Morchella or Gyromitra does 



1 These Researches, Vol. I, 1909, p. 248. 



2 Vide supra, p. 262. 



^ R. Falck, " Ueber die Sporenverbrcitung bei den Ascomyceten. I. Die radio- 

 sensiblen Disconiyceten," Mycologische Untersuckungen und Berichte von R. Falck, 

 Bd. I, Heft II, 1916, pp. 126-127. 



