﻿Vol. 25 



No. 10 



BULLETIN 



OF THE 



TORREY BOTANICAL CLUB 



OCTOBER 1898 



American Ferns— I: The ternate Species of Botrychium. 



By Lucien Marcus Underwood. 



The species now included in the genus Botrychium represent a 

 clearly marked group of plants which are in many cases quite 

 closely allied, a fact that has led to a considerable difference of 

 opinion regarding the limits of the species. Two groups of the 

 genus are made up of species that in their extreme forms approach 

 each other, but still maintain certain characteristics of their own. 

 So close is this approach that in the case of certain poorly pre- 

 served herbarium specimens it is difficult or sometimes almost im- 

 possible to distinguish the species, which in their living forms or 

 even in well-preserved material are not to be confused. Of 

 these two groups, one is composed of the species B. Lunaria, B. 

 borcale, B. lanceolatum and B. matricariacfoliiim, which in America 

 present a few peculiar modifications which are not, perhaps, of spe- 

 cific importance. The second group, known as the " ternata" group, 

 is made up of the diminutive B. simplex in which two or more 

 species have been confused, and the series of widely distributed but 

 well-marked species that were confused with B. ternatum of Japan 

 by Milde who has been followed more or less implicitly by English 

 and American botanists. While it is evident that in some cases 

 we must depend to a certain extent 01% habit and foliar cutting 

 rather than on spore characters in order to separate the various 

 species, in the great number of cases there are supplementary 

 characters that will aid in their recognition. It is, of course, 



o WW 



possible to assume a wide degree of variation in characters and 



[Issued 15 October.] ( 521 ) 



