SOME FEATURES OF FUTURE FERN STUDY. 



By Lucien M. Underwood. 



While at the great Kew collection of ferns in 1898 studying 

 the species represented in America and following the sequence 

 of "Synopsis Filicum," in accordance with which that collection 

 is arranged. I made the following note in the genus Polypodium: 

 "186. P. vulgar e. The following species at least are involved: 



(1). P. vulgar e. X. Europe; (2). P. serration; (3) P. 



Madeira: (4). P. Japan, frond coiling; (5). P. 



Rydberg's small form." The South European P. serratum (2) 

 by many continental botanists is now held to be distinct, as is 

 also the luxuriant species (3) from Madeira. Since 1898, Mr. 

 Maxon working independently has come to the same conclusions 

 as myself regarding the forms (4) and (5) and has described 

 them both as new species. 



The above incident illustrates the first advance that will be 

 made in the future study of our American ferns, viz. : the de- 

 limitation of closely allied species that have hitherto been tied 

 up in specific groups under single names. Something has been 

 done in this direction among our species of Botrychium, of 

 Sclaginclla, of Lycopodium, and of Polypodium, in all of which 

 groups more work still remains to be done. But there are other 

 groups in which delimitation is necessary to distinguish species 

 and varieties more carefully. Among these we may mention 

 Asplcniuni filix-focniina on which Mr. Gilbert has made a pre- 

 liminary study; Dryoptcris spinulosa on which Mr. Davenport 

 made his maiden study over a quarter of a century ago; Wood- 

 sia obtusa, Filix frogilis, Polystichum munitum, and perhaps 

 others. It is not the random description of some sport or freak 

 as a "var. cristata" or "var. furcata" that we want. Such so- 

 called varieties are of no value from a taxonomic standpoint ; 

 they are as unnecessary as they are irrational. Neither have 

 such varieties as "var. incisum" of Polystichum acrostichoides 

 and "var. Hortonac" of Asplcnium platyncuron, freaks likely to 

 occur on the same plant as normal leaves, any more substantial 

 standing. Much less do we want the refinements of such puerili- 

 ties as forma this and forma that, which have no semblance of 



