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MAXON—STUDTES OF TROPICAL AMERICAN FERNS. 475 



minute diagnostic characters are noted upon painstaking study. Too 

 few trustworthy modern data are available in published form to 

 permit of more than general deductions as to geographic distribution. 

 The problem often is, at present, to determine wliother viii'iations 

 noted are local and essentially indiAddual or, rather, are susceptible^ 

 of correlation wnth geographic and pliysiographic factors. 



In this connection the importance of further field work should 

 not be underestimated. AVith the important exception of Santo 

 Domingo and certain large areas in Cuba the "West Indies have been 

 fairly well covered within recent j^ears. Tliere remain on tlie Xorth 

 American continent Nicaragua, Salvador, TTonduras, and the vast 

 humid region of eastern Mexico. To the extreme south is Panamaj 

 connecting geogi'aphically the two continents, its ilora nearly un- 

 known but almost certainly containing the strong South American 

 element noted in that of Costa Rica immediately to the north. The 

 exploration of eastern Mexico at mid-elevations toward (he low- 

 lands seems especially desirable in order to bring to light many of 

 the species described during the first half of the last century. Ex- 

 ploration of the other regions mentioned, particularly of Panama, is 



m 



hardly less important, as certain to afford data bearing upon larger 

 problems. 



The writer wishes to extend his thanks to the curators of the 

 herbaria mentioned later for courteously placing at his disposal for 

 study numerous specimens which have been of material assistance. 



ASPLENIUM SALICIFOLIUM AND CONFUSED SPECIES. 



The Asplenium salicifolivm of LinnaMis lias been almost uni- 

 versally misidentified. It was founded \\\)in\ Plumier's plate 00, rep- 

 resenting a plant described by Plumier with the remark that he had 

 found it at " several places in the French islands of America." In 

 identifying the Linna^an species, then, we should expect to associate 

 this name with no very uncommon 2>lant of the AVest Indies. To 

 assist us there is a passable figure, somewhat idealized but yet show- 

 ing a plant since many times collected an<l rarely if ever r(^f erred to 

 under its right name— commonly, rather, as Asplenmm aiiriciilatirni 

 Sw\, a name given originally to l>razilian specimens. Ample Brazil- 

 ian material, lacking in American herbaria, might show the true .1. 

 auriculatum to be a different species from the West Indian specimens 

 passing under that name, though this is certainly to be doubted; but 

 in any event these "West Indian specimens undoubtedly represent the 



salicifol 



to 



intended to show. 



