



9 



A new Adiantum from New Mexico 



By Lucien Marcus Underwood 



In a small collection of ferns made by Professor F. S. Earle, 

 in New Mexico, there is one Adiantum that has been contused 

 with A. capillus-vcneris of Europe. I find fragmentary specimens 

 of the same plant in Wright's New Mexican collections of 1851- 

 52 as represented in the Columbia Herbarium. I have called the 





fern 



/ Adiantum modestum 



Rootstock widely creeping, often 10-12 cm. long, covered 

 with slender narrow pale brown scales ; leaf-stalks scattered, 

 slightly scaly at the base, purplish like the rachises ; lamina bi- 

 tripinnate, triangular-ovate, 10-12 cm. or more long, by 5—8 cn1, 

 or more wide ; leaflets 6-8 mm. wide, nearly as long as wide, 2r 

 5-lobed, but mainly 3-lobed, the incisions narrow and very shallow, 

 the margin in sterile leaflets evenly serrate, those bearing son 

 similarly serrate between the sori ; basal angle ranging from 90 - 

 180 , the stalk and basal veins greenish white, or the former 

 slightly tinged with brownish ; sori oblong, 2-3 times as long as 

 wide ; veins 3-5 times forked, conspicuous ; texture firm. 



Roswell, New Mexico. " Abundant on rocks and grassy 

 points overhanging the water of North Spring River," 3 August, 

 1900, F. S. Earle, no. 261 (type). New Mexico, Wright, no. 

 2123, 1851-52. 



A plant related to A. c a pillus -veneris but differing from it in 

 the smaller, less incised leaflets, their more rounded compact shape* 

 in the fewer narrower sori, in the light-colored stalks to the leaf- 

 lets, and in general habit. 



The European specimens of A. capillus -veneris are usually 

 much more laciniate than the American, but in A. modestum the 

 leaflets are barely trilobed with very shallow sinuses. 



Professor Eaton in his Ferns of the Southwest called attention 

 to the fact that the Southwestern forms of A. capilhis-veneris were 

 less divided and more rounded than the typical form of the species 

 and may have had in mind Wright's New Mexican plant which 

 was one of the few cited in that work. That character, however, is 



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