PREFACE 



There is developing an increasing demand for courses 

 in genetics adapted to the needs of botanical students, 

 and teachers of botany have asked repeatedly for a 

 suitable text. A number of texts on heredity and evo- 

 lution have appeared, but these have contamed far too 

 little genetics. On the other hand, there are several 

 very thorough texts on certain phases of genetics, but 

 these have been more in the nature of monographs than 

 texts. They have focused on too limited a field to give 

 the reader any general appreciation of genetics as a 

 whole and frequently have been too difficult for the 

 uninitiated to appreciate at all. Walter's Genetics 

 is an admirable elementary text, but is not exactly 

 adapted to the needs of the young botanist. All texts, in 

 fact, have emphasized animal genetics more strongly 

 than the student of botany needs, except certain books 

 on plant breeding, which, however, are general in nature 

 and give little attention to theoretical genetics. In 

 short, the subject has been changing so rapidly that no 

 one has ventured to write a general authoritative text.' 



The group that the present book is intended to serve 

 primarily comprises those who intend to make botany 

 their profession and who, although not as yet specialists, 



" After the manuscript of this text had gone to the printer, there 

 appeared a book by Babcock and Clausen, entitled Genetics in relation 

 to agriculture. This is "a general authoritative text," for it contains a 

 treatment of both plant and animal genetics, well suited to a thorough 

 year's course in genetics. 



