ASPLENIUM PARVULUM. SMALLER EHONY SPLEENWORT. 67 



not, however, very likely to be looked upon by many eyes, as it 

 is one of the rarest of our native species ; being so rare, indeed, 

 that, as far as our knowledge extends, it has never yet been 

 described in any work published in the United States. For 

 this reason we have had to go to a French memoir on the ferns 

 of Mexico for the description which, in accordance with our 

 plan, we have placed at the head of our chapter. The specimens 

 from which our drawing was made were kindly furnished to us 

 by Mr. Jackson Dawson, of the Arnold Arboretum, and came 

 from the southern part of the Alleghany Mountains. Mr. John 

 H. Redfield, of Philadelphia, has found the species on Salt Pond 

 Mountain, in Virginia, and in Carter County, Tennessee. In 

 the latter locality it grows together with Caniptosorus r/iizo- 

 pJiylhis, just as Asplcnium cbeiicum often does. 



Many good botanists, aware of the great variability of ferns, 

 are disinclined to allow to Asplcnium parviilum the honor of 

 being a distinct species, and regard it as a mere variety of A. 

 cbcncmn, or Ebony Spleenwort. In illustration of this varia- 

 bility, it will be noticed that our drawing, which is a very faithful 

 reproduction of nature, differs in some respects from the descrip- 

 tion of a Mexican form, quoted from the work of Mertens and 

 Galleotti. The fronds in our specimen, for instance, are twice 

 the length given in the description, although this may be 

 accounted for by the different soil which produced the ditfcrcnt 

 specimens. In Tennessee our species grows on soapstone rocks, 

 and these may be more congenial to it than the " calcareous and 

 porphyritic rocks in the Eastern Cordilleras " or " the shady and 

 humid spots " in the environs of Capulalpan and the Hacienda 

 del Carmen, where it is found in Mexico, according to the 

 authors quoted. There are other slight differences, which the 

 reader can easily detect himself, and which are not characteristic 

 enough to be ever regarded as of specific importance. The 

 points of difference between Asplenmm cbcncuin and AspUiuum 

 parvjchun, which strike us most strongly, are principally two. 

 The first of these points is that the veins which diverge from 



