2 24 THE PLANT WORLD. 



becoming' fertile. Eighteen species of ferns of the northeastern 

 United States are discussed in as many chapters, with an intro- 

 ductory chapter on the development of the fern leaf. The treat- 

 ment of the subject is both original and scientific. The illustra- 

 tions are of the kind that " really illustrate," and are an attrac- 

 tive feature of the book. M. M. B. 



