MAXON—STUDIES OF TROPICAL AMERICAN FERNS. 561 
Scales of the lamina very 
humerous, tortuous, 
pale, linear-attenuate 
from a small rounded 
base, coarsely fimbri- 
ate-dentate........... 20. P. oulolepis. 
marginate...........2.-2- eee eee eee ee eee 21. P. monosorum. 
1. Polypodium furfuraceum Schlecht. & Cham. Linnaea 5: 607. 1830. 
Polypodium nivosum Fée, Mém. Foug. 8: 89. 1857. 
Polypodium macbridense Shimek, Bull. Lab. Nat. Hist. Univ. Iowa 4: 199. 1897. 
Polypodium margallit Rovirosa, Pter. Mex. 206. 1910. 
TYPE LOCALITY: Near Jalapa, Mexico. 
DISTRIBUTION: Common from Mexico to Panama, at 200 to 1,800 meters 
elevation, ascending casually to 1,750 meters. 
ILLUSTRATIONS: Shimek, op. cit. pl. 20. f. 6-9 (as P. macbridense) ; Rovirosa, 
op. cit. pl. 388A. f. 1-5 (as P. margaliii). 
Fournier, in his treatment of this species, recognizes three varieties: (1) 
The typical form, with which Fée’s Polypodiuwm nivosum is doubtless synony- 
mous, as there stated; (2) a variety 8, which is supposed by him to include 
Fée's Polypodium cryptocarpon; and (3) var. y coronulatum. As to P. 
cryptocarpon, it may be said that Fée’s description, though imperfect, points 
unmistakably to the species usually called P. skinneri, rather than to P. fur- 
furaceum, Fournier’s third form, y coronulatum, has not been identified by 
the writer. 
The species was next described as P. macbridense by Shimek upon Nica- 
raguan specimens, his illustration representing the ordinary form. The refer- 
ence of Polypodium margallii to P. furfuraceum is also tolerably certain, the 
venation agreeing exactly. 
There is noted in P. furfuraceum a great amount of variation in the color 
of the scales upon both the rhizome and the under side of the lamina, the ex- 
tremes in color being whitish and clear yellowish brown, with numerous inter- 
‘mediate shades in different plants or even upon fronds of different age in the 
same plant. The shape of the scales also is variable. Those of the growing 
part of the rhizome are commonly deltoid-lanceolate, although from their being 
subappressed and densely imbricate they appear more or less subulate. The 
venation of a pinnule is shown well in Rovirosa’s figure above cited. 
Polypodium furfuraceum grows usually upon tree trunks but occasionally 
also upon shaded banks in well-rotted humus. The following specimens are in 
the U. S. National Herbarium: 
Mexico: Cérdoba, Veracruz, Bourgeau 14389; Orcutt 3208; Fink 854. 
Zacuapan, Veracruz, Purpus 2167. Near Jalapa, Veracruz, Rose ¢& 
Hay 6376. Between Rosario and Colomas, in the foothills of the 
Sierra Madre, Sinaloa, Rose 1642. Orizaba, Veracruz, alt. 1,200 meters, 
Seaton 11. La Barranca, Michoacin or Guerrero, on wet rocks, Lan- 
glassé 317. Hills of Patzcuaro, Michoacfin on oak trees, Pringle 3357. 
Between Chicoasen and San Sebastifin, Chiapas, alt. 1,200 meters, 
Collins & Doyle 176. Alzada, Colima, Orcutt 4637. 
GUATEMALA: Cubilquitz, Alta Verapaz, alt. 350 meters, von Tiirckheim 
(J. D. Smith, no. 7723); von Tiirckheim II. 31. Santa Rosa, Depart. 
Santa Rosa, alt. 900 meters, Heyde & Lug (J. D. Smith, no. 3252). 
San Juan, Utap4, Depart. Santa Rosa, alt. 1,350 meters, Heyde & Lug 
