576 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
thick, rigidly spongiose-coriaceous, the upper surface light or grayish green, 
glabrous, and non-paleaceous, the lower surface grayish green to distinctly 
yellowish,’ glabrous, obviously but sparsely paleaceous, the scales broadly ovate 
to deltoid-ovate, long-acuminate, 1 to 1.5 mm, long, attached above the cordate 
base, castaneous, slightly paler toward the irregular bidentate margins, the 
cells mostly short to elongate-hexagonal, their outer walls transparent, the par- 
tition walls thick but yellowish-translucent; marginal row of cells transversely 
linear. 
Type in the U. 8. National Herbarium, no. 336056, collected near Saltillo, 
State of Coahuila, Mexico, altitude about 1,600 meters, April 15 to 30, 1898, 
by Dr. Edward Palmer (no. 65). A second sheet of the same number is also at 
hand. 
The present species has hitherto been included in P. plebejum by Eaton, 
Davenport, and the writer in reporting upon the collections of Dr. Edward 
Palmer, who is apparently almost the only one to have collected it. The ample 
material brought together by him is singularly uniform and indicates that this 
is the dominant and characteristic member of the plebejum group in the States 
of Coahuila and San Luis Potosi. 
Polypodium guttatum is at once distinguishable from the allied species P. 
plebejum and P. oulolepis by its different aspect and more particularly by the 
pecularity of the scales of the lower side of the lamina. These in P. plebejum 
are rather slender, few, and often so minute as to be nearly invisible to the 
naked eye; whereas in P. guttatwm they are more numerous and of different 
Shape and though scattered are large and conspicuous, giving a speckled ap- 
pearance to the lamina. Polypodiwm owlolepis also has numerous scales be- 
neath, but they are narrowly attenuate and of different structure, being coarsely 
lacerate-dentate. Although the rhizome scales of all three species are similar, 
it may be noted that the median stripe in P. plebejum and P. oulolepis consists 
of black opaque cells so strongly sclerotic that their distinctness is lost, while in 
P. guttatwm the lumina of the dark median cells are usually apparent, being 
often rather large, 
Besides the type the following specimens are in the U. 8. National Herbarium: 
Mexico: Same locality data as the type, Palmer 653. Region of San Luis 
Potosi, alt. 1,800 to 2,400 meters, 1878, Parry & Palmer 973. Near San 
Luis Potosi, same State, Palmer 664 in 1898; Palmer 99 in 1902. 
Alvarez, State of San Luis Potosf, at base of trees and upon the shaded 
under side of large oaks, alt. 2,400 meters, Palmer 442 and 4484 in 
1902. Mountains 12 to 14 leagues south of Saltillo, State of Coahuila, 
Palmer 1873 in 1880. Sierra de Pachuca, State of Hidalgo, Rose & 
Painter 6717. Without exact locality data, J. G. Schaffner 56. 
EXPLANATION OF PLATE 40.—Blades of two middle-sized fronds of the type collection 
of Polypodium guttatum, the sterile one showing especially well the guttate under sur- 
face. Natural size. 
20. Polypodium oulolepis Fée, Mém. Foug. 8: 86. 1857. 
Polypodium madrense J. Smith in Seem. Bot. Voy. Herald 338. 1854. 
TYPE LOCALITY: “ Huatusco, Orizaba et au Popocatepetl, & 2,700 métres d’alti- 
tude (W. Schaffner, nos. 191, 192 et 274 partim).” 
DISTRIBUTION : Central Mexico, at 2,400 to 2,700 meters altitude. 
ILLUSTRATION: J, Smith, op. cit. pl. 73 (as P. madrense). 
The species name oulolepis is applied as below partly from Fée’s description 
but principally upon the basis of John Smith’s illustration and of specimens 
*“ Olive ocher ” and “ sulphine yellow ” of Ridgway’s “Color Standards and 
Nomenclature,” 1913. 
