22 American Fern Journal 



African continents. Of the total number of species 



listed, twelve are known to occur only on the Seychelles 



Islands. Two of these are described as new, Asplenium 



complanatum, and Elaphoglossum Hornei. Twenty of 



the seventy-eight occur also in the American tropics. 



The remaining forty-four are species of Asiatic or African 

 distribution. 



Christensen, Carl. A monograph of the genus Dryop- 

 teris. Part 1. The tropical American pinnatifid- 

 bipinnatifid species. Kgl. Danske Vid. Selsk. Skr. VII, 

 10: 55-282. fig. 1-1$, 1913. 



The paper now under consideration is undoubtedly 

 the most extensive and at the same time most thorough 

 fern monograph ever published. Two hundred and 

 eighty species are treated in its two hundred and 

 thirty odd pages. The results are based on the study 

 of approximately ten thousand specimens, obtained 

 largely by loans from the leading herbaria of Europe 

 and America. The actual significance of these facts 

 will hardly be appreciated except by those who have 

 carried on careful taxonomic research, but it may be 

 noted that the paper under review represents very many 

 laborious hours scattered through a period of years. 

 Its value for fern classification is commensurate with 

 the time and labor involved. 



No attempt will be made here to review in detail its 

 findings. Mention may be made, however, of some 

 interesting facts connected with fern distribution. A 

 pronounced difference occurs between the fern flora of 

 Southern Brazil as compared with the West Indian- 

 Andean regions which have much in common. Only 

 fourteen species are found in both regions and even the 

 forms of these which occur in both regions differ some- 

 what. Three species of the two hundred and eighty 

 occur also in the eastern hemisphere. One of these, 



