MAXON—STUDIES OF TROPICAL AMERICAN FERNS. 411 
Polypodium rosenstockii Maxon, sp. nov. 
Plants epiphytic, with 8 to 12 pendent fasciculate fronds, 15 to 40 cm. long. Rhi- 
zome erect or oblique, 1 to 1.5 cm. high, about 5 mm. in diameter, freely radicose 
below, the whole upper half conspicuously paleaceous, the scales yellowish brown 
(bright brown in mass), linear, rather lax, up to 6 mm. long, semitranslucent, sub- 
tortuous, somewhat plicate, the margins subentire, bearing an occasional minute 
unicellar gland-like process; stipes 1 to 3 cm. long, 0.5 to 0.7 mm. thick, dull light 
brown, terete, bearing a few very slender yellowish hairs about 2 mm. long, these 
readily deciduous; lamina oblanceolate (in small plants) to linear, 12 to 38 cm. long, 
2 to 3.2 cm. broad, subpinnatisect throughout, gradually attenuate toward the base, 
usually more abruptly so toward the short-caudate apex; pinnules 15 to 65 pairs 
entire, spreading or slightly oblique, the lowermost ones very broadly so, short- 
decurrent, almost vestigial, often far apart; pinnules in general narrowly triangular- 
oblong, slightly decurrent to the narrowly acute sinus, connected by a costal wing less 
than 1 mm. broad; midvein slightly flexuous, medial except at the arcuate base, 
here parallel to the lower margin; veins 8 to 12 pairs, very oblique, wholly immersed, 
evident only by transmitted light, mostly once forked at or beyond their middle; 
sori 7 to 10 pairs, superficial, terminal upon the short distal branches, much nearer to 
the margin than to the midvein, round, about | mm. in diameter; sporangia glabrous, 
the annulus with 14 cells; spores triplanate, pale, minutely granulate. Leaf tissue 
very rigidly spongiose-herbaceous, freely but minutely viscid-glandular beneath, 
sparingly so above. 
Type in the U. 8. National Herbarium, no. 692068, collected near Caldas, Minas 
Geraés, Brazil, in 1851 and distributed as no. 1442 of Series III of the Regnell Her- 
barium under the name Polypodium pendulum Swartz. 
The following additional collections, both representing younger but fully fertile 
plants and both distributed as P. pendulum, are in the U. 8. National Herbarium. 
Brazit: Serra do Mar, Sao Paulo, alt. 1,000 meters, Wacket (Rosenstock, nos. 288 
and 439.) 
Although the type number of this species was distributed long ago as Polypodium 
pendulum Swartz and was subsequently listed under that name,’ it can scarcely be 
regarded as a near relative of that species, which may be identified readily by means 
of Schkuhr’s excellent plate ? and Jenman’s vary good description.2 Polypodium 
pendulum, which is probably confined to the West Indies, differs wholly in its slender, 
lax, delicate fronds, short, distant pinnules, rigidly long-setose sporangia, and long- 
ciliate, conspicuously reticulate rhizome scales. 
Polypodium rosenstockii is allied rather to P. curvatum Swartz, which differs specif- 
ically in the much greater size of all its parts, in its exstipitate fronds, in its thicker 
and decidedly whitish pulverulent leaf tissue, and in its rigidly short-ciliate rhizome 
scales, as well as in numerous other characters. 
Both P. pendulum and P. curvatum are represented in the National Herbarium by 
very complete material which was collected by the writer in Jamaica, the type 
locality, and was compared with Swartz’s types at Stockholm by Dr. Lindman. The 
latter species was described and figured by Fée as Polypodium inaequale Fée.* 
NOTE UPON PELLAEA ARSENII. 
This species, described’ by Christ from a single coeclltion (Arséne 
2496), is a common one in Mexico, whose distinctness had long been 
recognized by Dr. L. M. Underwood and the writer, independently 
1 Arkiv Bot. 1: 231. 1903. 4Mém. Foug. 11: 47. pl. 12./. 3. 1866. 
2 Krypt. Gewachs 1: pl. 10. 1804. 5 Not. Syst. 1: 233. 1910. 
3 Bull. Bot. Dept. Jamaica IT. 4: 118. 1897. 
