4 INTRODUCTION 



more within a few hours, and continues for days or weeks. It was 

 therefore possible for me to collect a stock of these fruit-bodies in 

 autumn, to revive them at will, and thus to study the liberation of 

 spores throughout winter and spring. 



There seems to be but little literature dealing with the liberation 

 of spores of Hymenomycetes. Some observations of Brefeld, 1 given 

 in a footnote in his description of the life-history of Coprinus ster- 

 corarius, will be mentioned and criticised later on. Richard Falcjv - 

 has published a paper on the scattering of spores of Basidiomycetes, 

 in which he has given an account of the gradual accumulation of 

 spore-deposits on upper surfaces in closed chambers. He did not 

 succeed in actually seeing the spores in the air, but his experiments 

 showed that they are carried with remarkable ease by the slightest 

 air-currents. This fact can be verified directly and very simply by 

 means of my beam-of-light method, and rendered capable of mathe- 

 matical treatment by an exact determination of the rates of fall of 

 the spores in still air. 



A visible spore-discharge from a fruit-body has been occasionally 

 observed as a very rare phenomenon by a few botanists. To the 

 records of Hoffman, H. von Schrenk, and Hammer 3 will be added 

 nry own upon the visible discharge of spores from fruit-bodies of 

 Poly par us squa mosus. 



In his translation of Pfeffer's Physiology of Plants, Ewart 4 added 

 a brief statement of some of my then unpublished conclusions con- 

 cerning the liberation and fall of spores. The evidence in support 

 of these conclusions is brought forward for the first time in this 

 book. 



In an account of the biology of Polyporus squamosus, I recorded 

 a number of observations upon the fall of spores in that species, and 

 gave an illustration showing the paths taken by the spores in falling 

 down the hymenial tubes. 5 A subsequent calculation, however, 



1 Brefeld, Botanische Untersuchungen iiber Schimmelpike, III. Heft, pp. 65, 66. 



2 R. Falck, "Die Sporenverbreitung bei den Basidiomyceten," Beitriigi zur 

 Biologic der Pflanzen, Bd. IX., Heft 1, 1904. 



3 For references, vide infra, Chap. VI. 



4 Pfeffer, Physiology of Plants, translated by A. J. Ewart, vol. iii. 1906, p. 416. 



5 Buller, "The Biology of Polyporus squamosus, Huds., a Timber-destroying 

 Fungus," The Journal of Economic Biology, vol. i., 1906, p. 131. 



