A STUDY OF CERTAIN MEXICAN AND GUATEMALAN 
SPECIES OF POLYPODIUM. 
By Witiram R. Maxon. 
An attempt to determine a small collection of Mexican ferns made 
by Dr. J. N. Rose in 1901 has brought to my attention the fact that a 
number of very variable as well as perfectly distinct forms have been 
referred commonly to either Polypod/um subpetiolatum or P. biserra- 
tum, and that the proper application of the latter name has long been 
amatter of uncertainty. The present paper, based upon studies of 
material in practically all leading American herbaria, is offered as the 
result of an effort to reduce the existing confusion. The several 
species here proposed as new are certainly distinct from subpetiolatuin, 
and several of them are not even closely related to that species. It is 
not absolutely certain that Diserratum is identical with swhpetdolatum, 
but the evidence gained from specimens at hand strongly indicates such 
a conclusion. 
My thanks are due to the several botanists and curators of the her- 
baria mentioned hereafter@ for the loan of specimens, and particularly 
to Professor L. M. Underwood for helpful suggestions. 
Polypodium subpetiolatum Hook. in Benth. Pl. Hartw. 54. 1840. 
The original description, published by Hooker, is as follows: 
Polypodium (Hupolypodium) subpetiolatun, Hook. Ms., fronde ovato-lanceolata 
pinnata, rhachibus costa venis subtus marginibusque pubescenti-hirsutis, pinnis 
alternis remotis lanceolato-acuminatis undique serrulatis subcoriaceo-membranaceis, 
inferioribus basi oblique truncatis brevissime petiolatis petiolis superne alatis, superi- 
oribus basi oblique cuneatis sessilibus, supremis basi decurrentibus adnatis, soris 
rotundatis uniserialibus.—Caudex repens, crassitie pennae anserinae, squamosus. 
Stipes 4-5-pollicaris. Frons pedalis. Venae obliquae 2-3-4-furcatae, basi nigri- 
cantes, venula infima superne sorifera, reliquae fere ad marginem attingentes, apicibus 
clavatis. (Hooker. )—Regla. 
Hooker redescribed and figured the species without mention of additional speci- 
mens in the Icones.? The emended description contains no mention of margins 
an this paper the letters C, E, G, M,N, 8, U, and Y refer respectively to the 
Columbia University Herbarium, the D. C, Eaton Herbarium at Yale University, 
the Gray Herbarium of Harvard University, the Missouri Botanical Garden Herba- 
rium, the U.S. National Herbarium, the private herbarium of Capt. John Donnell 
Smith, the Underwood Herbarium, and the New York Botanical Garden Herbarium. 
b Hook. Ic. Pl. 4: pl. 891-392. 1841. 
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