—35— 



the only ones which he seems to imply have been found 

 in this country are auritum, cambricwm and cristatum. 

 Variety auritum was given on the authority of Prof. John 

 Robinson, but as I have never seen any American speci- 

 mens of that variety, and as other forms have been so 

 often mistaken for that, it is not included in my list. 



I have arranged the varieties in four groups, as fol- 

 lows : 



Group I. With normal fronds. 



Group II. With serrate or sinuate or lobed pinnae. 



Group III. With branched fronds. 



Group IV. With crested fronds. 



GROUP I. 



1. Var. angustum Muell. The peculiarity of this va- 

 riety is that the pinnae are long lanceolate, acuminate and 

 often doubly serrate. It includes Maxon's deceptum, 

 Millspaugh's biserratum, and Gilbert's acuminatum. 

 Habitats: West Virginia (Millspaugh, Maxon) ; Fox' 

 Fall, Herk. Co., N. Y. (Gilbert) ; Hancock, N. Y. (Mrs. 

 Britton) ; Shandaken, N. Y. (Marv F. Miller) ; Onteora, 

 N. Y. (Anna M. Vail). 



2. Forma attenuatum (Milde). A rather large, slender 

 form, 36 cm. or more long, 8 cm. wide, with many bluntly 

 acute pinnae, which are alternate. Tip of frond slender, 

 2 cm. long, slightly sinuated, fruit often extending up 

 into it. Hab. : Lake Sunapee, N. H. (C. E. Waters). 



3. Forma marginalc f. nov. This represents a very 

 regular form of the species, but it is chartaceous rather 

 than coriaceous. Its distinguishing feature is that the 

 fruit dots are marginal instead of central or near to the 

 costa. As the sori are usually situated at the end of the 

 anterior venule in this species, and as that venule extends 

 very nearly to the edge in this form, instead of half way 

 between the edge and costa. it follows that the sori ex- 

 tend in a distinctly marginal row nearly from the midrib 

 of the frond to the ends of the pinnae. In all the fronds 



