188 THE PLANT WORLD 



members of the Harriman expedition secured 254, even without the aid 

 of a professional mycologist. 



The lichens are treated by Professor Clara E. Cummings, who enumer- 

 ates 462 species. The mosses number 280 ; this portion of the work, by 

 Cardot and Theriot, together with the Algae, by Saunders, and the 

 Hipatics, by Evans, had been already published elsewhere. The ferns 

 are treated for the first time by Professor Trelease. 



The book is a superb example of typography, presswork, and binding, 

 and the plates are fully up to the standard of scientific requirements. 



c. L. P. 



Plant Breeding. Being Five Lectures upon the Amelioration of Do- 

 mestic Plants. By L. H. Bailey. Third edition. New York: The 

 MacMillan Company, 1904. 



As Professor Bailey well said in the preface to the first edition of this 

 little work, which appeared in 1895: "There is no subject associated 

 with the care of plants respecting which there is so much misapprehension 

 and imperfect knowledge as that of the origination of new forms." To 

 the uninitiated it seems a marvel that there should be so many ' ' new ' ' 

 or ' ' improved ' ' plants and vegetables placed on the market each year, and 

 the suspicion has gained wide acceptance that many of these are but 

 exploitations of old things under new names. While in some cases this 

 may be true, the fact remains that actual new varieties are constantly 

 appearing, and the mystery surrounding their production is, in the popular 

 mind, profound. But it is coming to be known that there are certain 

 more or less definite laws underlying and governing the production of 

 new races, and while we do not by any means possess full knowledge on 

 the subject, each season marks a decided advance. Particularly has this 

 advance been rapid within the eight years intervening between the first 

 and the present editions of this book, during which time there has been 

 a ' ' re-defining of what a variety is ; thereby we have come to recognize 

 the fact more clearly than heretofore, that not all differences in plants 

 are of equal importance or significance. ' ' More especially has there come 

 to be a growing belief that the offspring of hybridization follow definite 

 laws. The facts as at present understood are well set forth in the book before 

 us, of which lack of space forbids more than enumeration of the lecture 

 headings. The first is devoted to the fact and philosophy of variation, 

 the second to the philosophy of the crossing of plants considered with 

 reference to their improvement under cultivation, while the third tells 

 how domestic varieties originate, the fourth discusses recent opinions 

 on the evolution of plants, and the final lecture deals with pollination or 

 how to cross plants. A glossary, full bibliography of the subject, and a 

 careful index completes the book. It is perhaps needless to add that this 

 book must be in the hands of every intelligent devotee of this fascinating 

 subject. F. H. K. 



