REVIEWS 675 



that are shot away violently (it is absent in Gasteromycetes), and to the 

 excretion of a drop of water at the hilum immediately before spore discharge. 

 The drop of water increases the weight of the projected sporr, and so causes 

 the projectile to be carried a greater distance away from the hymenium than 

 if the spore were dry ; it is attached at the forward end of the spore and causes 

 the latter to adhere to any surface that it may come in contact with. In 

 Vol. I of the Researches it was shown that there was a considerable discrepancy 

 between the time of fall as calculated from Stokes' law and the observed 

 figures ; it is here pointed out that the increased weight of the spore due to 

 its carrying with it the drop of water mentioned above would partly, if not 

 completely, explain the difference between the observed and the calculated 

 figures. 



Other chapters are concerned with the Red Squirrel and Slugs as myco- 

 phagists, with the spore discharge in Hydneae, Clavariae, Polyporeae, and the 

 questions of the efficiency of such fruit-bodies for spore discharge. The author 

 is to be congratulated on a very notable work and an extremely fascinating 

 one. He has certainly proved his contention that " the form and arrange- 

 ment of parts exhibited in the sporophore of the Common Mushroom and its 

 allies appear to be no less beautifully fitted for the efficient production and 

 liberation of spores than are the form and arrangement of Orchid flowers for 

 securing successful pollination by insects." 



The Fundamentals of Fruit Production. By Victor Ray Gardner, 

 Frederick Charles Bradford, and Henry Daggett Hooker, 

 junr., of the Department of Horticulture of the University of Missouri 

 [Pp. xvi + 686.] (New York and London : McGraw-Hill Book 

 Company, 1922. Price 22s. 6d.) 



Although books abound dealing with the practice of horticulture in general 

 or of particular branches of it, the literature of the scientific principles under- 

 lying horticultural practice remains for the most part in the form of records 

 of original research scattered through scientific journals or published as 

 reports from agricultural and horticultural research stations. For this 

 reason, if for no other, the work under review would find a welcome. The 

 authors have, however, covered the field so thoroughly, and presented the 

 principles of fruit-growing and the facts on which the principles rest so well, 

 that this work must for long remain a classic not only of horticultural, but 

 also of scientific botanical, literature. 



The book is divided into seven sections dealing respectively with water 

 relations, nutrition, temperature relations of plants, pruning, fruit-setting, 

 propagation, and geographic influences in fruit production. As the authors 

 rightly state, " The plant's growth and functioning depend on the nature of 

 the environment and the adjustment thereto and not directly on cultural 

 practices, which only modify the relation of the plant to the environmental 

 complex." Thus horticultural practices are not prominent in the headings 

 of the sections and chapters. This is as it should be in a book dealing with 

 the scientific principles of a plant study ; nevertheless, as cultural practice 

 may alter the conditions of the environment, these cannot be neglected even 

 in a book dealing thoroughly with principles, and we find adequate references 

 to cultural practices throughout the work. 



The book can be thoroughly recommended not only to serious scientific 

 students of horticulture, but also to botanists who wish to possess a summary 

 of the present position of our knowledge of an aspect of the growth of the 

 plant too often neglected. The adequate lists of literature at the end of 

 each section will be found useful to the student who wishes for further infor- 

 mation on the subjects dealt with. 



W. S. 



