368 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 52 



For the courtesy of the authorities of the U. S. National Museum 

 and the kindness of Captain Smith in lending me these rich collec- 

 tions I wish here to express my most sincere thanks. I have studied 

 these specimens with unusual satisfaction and pleasure, owing to 

 their careful preparation and the detailed data of locality, altitude, 

 and conditions of habitat, in which respect they very far surpass 

 most of the material with which I had previously worked. I have on 

 this account been able to gain a more exact idea of several species 

 and of their distribution. 



In the following paper 9 species are described as new, and 3 older 

 species not mentioned in my "Revision" are included ; thus, alto- 

 gether, 94 American species of this narrow group are now dealt 

 with by me. About a dozen more have been described by Jenman 

 and Sodiro, but of these I have seen no specimens. Recently Dr. E. 

 Rosenstock has described a new species of this group from Bolivia, 

 and he sends me another apparently new species from Ecuador. The 

 whole number of valid described species thus exceeds 100, but I have 

 no doubt that the number will eventually prove to be considerably 

 greater. In the vast amount of material examined by me are to be 

 found not a few fragments which, I believe, belong to undescribed 

 species. It is interesting to note that among the few species known 

 from Bolivia at least 2 are new to science. From the Peruvian and 

 other parts of the Andes very few specimens are seen, but it is prob- 

 able that these regions possess a similar number of species to the 

 Andes of Ecuador, Colombia, and Costa Rica, and that not a few 

 will appear to be new. 



I have in my "Revision" pointed out a remarkable difiference be- 

 tween the species of southern Brazil and those of the Andes and the 

 West Indies, the fern floras of the last two regions showing an 

 intimate alliance. The rich collections of the U. S. National Herba- 

 rium show this alliance to be still closer than supposed. The occur- 

 rence of the Jamaican D. Thomsoni in Colombia (D. Stuehelii), of 

 the West Indian D. sancta in Guatemala, and of the continental D. 

 rudis in Jamaica are new examples of this relationship. 



In the preceding table is shown the distribution of the species 

 occurring north of Panama, as known to me. A "-{-" indicates that 

 the species is found in the country or island indicated; "( + )" that 

 it is recorded, but not surely in the true form; and an "*" that it is 

 endemic or hitherto not found beyond. 



In this table Costa Rica, Jamaica, and Guatemala figure as having 

 the largest number of species ; the other Central American republics 

 are not so thoroughly explored as the two named, but will probably 



