﻿THE FERN BULLETIN 



Vol. XVI APRIL, 1908 No. 2 



A PEDATE BRACKEN. 



D dry o pteris pedata. 



BY WILLARD N. CLUTE. 



In the tribe Pterideae to which our common brake 

 or bracken (Pteris aquilina) belongs, there are at least 

 a dozen genera, among which may be mentioned as 

 typical Pellaea, Chilanthes and Lonchitis. The char- 

 acteristic recognition marks of the tribe are found in 

 the sori which are placed at the ends of the veins near 

 the margin of the frond, or upon a vein-like receptacle 

 connecting the tips of the veins, and covered with some 

 sort of an indusium formed by the reflexed margin of 

 the frond. With genera as with species, however, it is 

 easy enough to recognize typical and well-marked ex- 

 amples; the trouble arises in trying to draw the line 

 between those which shade off into other groups with 

 characters that make them as well placed in one as 

 in the other. In consequence of this, the limits of the 

 tribe are, in a measure, matters of opinion and botan- 

 ists are not entirely agreed as to just what genera 

 should be included in it. In the same way, the genus 

 Pteris for which the tribe is named, consists of a 

 hundred or more species differing so greatly among 

 themselves that the different groups into which they 

 naturally separate are often considered to be distinct 

 genera as is often the case with similar groups in Poly- 

 podium and Nephr odium. 



It thus happens that the subject of this sketch some- 

 times finds itself in the genus Pteris and again in the 



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