308 Stosson: Notes oN TWO NorTH AMERICAN FERNS 
Tiirckheim (no. 3066). This specimen is figured on PLATE 7, 
FIGS.2and 4. It agrees exactly in character with the United States 
plant (FIG. 3). No differences are to be found in the venation, 
size of the cells and thickness of the cell-walls of the laminae and 
of the lips of the involucre, size and character of the spores, 
trichomes of the margins of the laminae, etc. 
This is not the first instance of species known to the United 
States occurring on the high mountains of Santo Domingo. Dr. I., 
Urban! has recently cited some six or seven species, at least three 
of which, Chimaphila umbellata (L.) Nutt., Sphenopholis obtusata 
(Michx.) Scrib., and Agrostis perennans (Walt.) Tuckerm., are to 
be found in the vicinity of New York City! One is a fern, Pellaea 
ternifolia (Cav.) Link, which, however, ranges from Chile to Texas. 
A new fern species has been unexpectedly added to the flora 
of the United States lately by the discovery of Dr. Rydberg and 
Professor Garrett, while collecting plants in Utah in the summer 
of 1911, of two small colonies of maidenhair, fast in the cracks 
of the wall of the Armstrong Cafion. The plants were found on 
the north side of a small branch of the cafion, near the Edwin 
Bridge. The two colonies grew in partial shade, less than a 
hundred yards apart, both imbedded in horizontal crevices of 
sandstone, under overhanging rocks. 
These plants represent an undescribed species, and I am in- 
debted to Dr. Rydberg for the privilege of describing it. It is 
related to Adiantum Capillus-Veneris, but differs in several par- 
ticulars, noticeably in the flexuose rachises, peculiarly tapering 
bases of the fertile pinnules, and long heavy indusia. It may be 
described as follows: 
Adiantum rimicola Slosson sp. nov. 
Rhizome creeping but often closely branched, thus making 
the fronds appear tufted, about 2 mm. in diameter, thickly chafty ; ; 
scales 4 mm. or less long, dark brown, linear or lanceolate, acumi- 
nate, entire or with one or more sharp lobes, long-celled; similar 
scales on the lower parts of the stipes; plant otherwise glabrous; 
stipes up to 15.3 cm. long, dark reddish-brown, flattened or some- 
what grooved on face, otherwise rounded; laminae up to 17.5 cm. 
long, up to I2 cm. broad, evateeeieia or ‘the smaller ovate-oblong, 
: Seiabole ApHiiaties 6: shes 1909. 
