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STUDIES OF TROPICAL AMERICAN FERNS-NO. 1. 



By William R. Maxon 



INTRODUCTION. 



In this and following papers it is the purpose of the writer to pre- 

 sent under a collective title some results of studies of tropical Amer- 

 ican ferns, especially those of the West Indies, ^Mexico, and Central 

 America. The matter is designed to include notes on some of the 

 earlier sj)ecies, corrections in nomenclature, descriptions of new 

 species and, wdien material warrants, revisions of certain genera and 

 smaller groups of species. 



A considerable number of the early species, of those even which 

 have figured longest in literature, are still imperfectly understood 

 and not infrequently appear under wrong names. To determine with 

 exactness these historic species is of much taxonomic importance. 

 The accomplishment of this, often a matter of extensive detail, is 

 made vastly easier than formerly to American students by the large 

 series of specimens gathered in recent years by American collectors; 

 but even Avith these at hand there remain other considerations wdiich 

 render the serious study of so variable a group more than ordinarily 

 difficult. As chief of these — aside from the usual insufficiency of the 

 diagnoses and the location of the historic early collections, with their 

 numerous types and frequently cited numbers, in European her- 

 baria — may be mentioned the lack of attention given in the past to 

 the matter of type localities and the failure to appreciate the fact of 

 the more or less definite geographical distribution of species. From 

 this there has resulted the irreatest confusion. 



( 



To illustrate: The extent of variation even in a suite of specimens 

 from a single locality in tropical America, these known absolutely 

 to constitute but a single variable though definitely restricted sj^ecies, 



is sometimes 



and this in no one genus and no one tribe 



little short 



of astounding. To such a series known under one name may have 

 been joined a closely allied group from some other and perhaps dis- 



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