PREFACE 



THESE pages contain a contribution to the physiology, mor- 

 phology, and physics of reproduction in the Hymenomycetes, and 

 also a record of some observations upon the discharge of spores 

 of 'Ascomycetes and of Pilobolus. Naturally many problems have 



^ been left unsolved, but I hope that the new data obtained will 



\^ give an added interest to some of our commonest plants. The 



delicate adaptations of structure to function, as revealed by a 



study of the fruit-body of a Mushroom, a Coprinus comatus, or 



^ a Polyporus, have provided me with no small cause for wonder- 

 ^ ment and delight, and they seem well worthy of the attention 



^' of all those who desire to understand more fully the vegetable 

 world by which they are surrounded. The value of the more 

 purely physical work must be left to physicists to decide. How- 

 ever, as showing how closely the various branches of science may 



^ be knit together, it is not without interest that the first direct 



V test of Stokes' Law for the fall of microscopic spheres in air has 

 . been carried out with the help of a lowly Cryptogam. 



The research, which has occupied five years, was preceded and 



'N suggested by a systematic study of fungus species in the field, in 

 which I was much assisted by Geo. Massee's British Fungus Flora 

 and M. C. Cooke's Illustrations of British Fungi. During the 

 winters the experimental work was carried on in my own laboratory 

 at the University of Manitoba, and during the summers in the 

 Physics and Botanical laboratories at the University of Birming- 

 ham. I have much pleasure in expressing my best thanks to 

 Professors Poynting and Hillhouse for the facilities accorded me. 

 I also wish to acknowledge my indebtedness to Dr. Guy Barlow 



