MAXON—STUDIES OF TROPICAL AMERICAN FERNS. 407 
with spreading reddish hairs 1.5 to 2 mm. long; lamina linear, 7 to 12 cm. long, 7 
to 9 mm. broad in the middle, obliquely pinnatifid nearly to the rachis, gradually 
narrowed at the short-caudate pinnately lobed apex, more abruptly narrowed at the 
base, the lower segments distant, decurrent, finally evident only as a minute wing 
upon the rachis, the whole lamina long-setose, conspicuously so near the apex of 
the segments and upon the upper side of the rachis (the hairs like those of the stipe); 
segments monosorous, oblique, 25 to 40 pairs, close, narrowly deltoid-oblong, slightly 
decurrent, obtusish, entire (except at the minutely crenulate apex), yellowish green, 
chartaceous; veins of the sterile segments simple, the strongly clavate apex easily 
seen upon the upper surface as an elliptical hydathode distant about 1 mm. from the 
apex; veins of the fertile segments once forked near the base, the thickened apex of 
each branch evident as a hydathode; sori nearly terminal upon the short proximal 
branch, round, arising about 0.7 mm, from the rachis and borne against it at maturity, 
then about 1.5 mm. in diameter; annulus consisting of 13 or 14 cells; spores sub- 
globose, minutely granulate. 
Type in the U. 8. National Herbarium, no. 833632, collected upon the forested 
upper slopes of the Volcdn de Barba, Costa Rica, February 6, 1890, by H. Pittier 
(no. 1928). 
Polypodium hyalinum is a member of the group of P. trichomanoides and probably 
finds its nearest ally in that species itself, from which it differs not only in the general 
appearance of its fewer fronds and in having the segments broader, more oblique, and 
not atall gibbous, but also very manifestly in its rhizome scales. These have the cells 
larger and relatively much broader and with partition walls distinctly thicker than 
in P. trichomanoides. They differ further in having from 10 to 17 spreading fragile 
hyaline cilia set closely upon each side of the apical half, the scales of P. trichomanoides 
being wholly devoid of cilia. Several similar species of this group have ciliate scales, 
but in these the cilia are dark brown and mostly longer and bristle-like. Polypodium 
hyalinum, which takes its name from the transparent cilia of the rhizome scales, 
may thus be readily distinguished by this unique character alone. It doubtless 
occurs upon other of the Costa Rican volcanoes. 
Polypodium blepharodes Maxon, sp. nov. 
Rhizome erect or ascending, about 1 cm. long, 2.5 mm. in diameter, abundantly 
radicose; fronds numerous, 8 to 15 cm. long, erect, closely fasciculate, subimbricate 
at the base and partially concealing the inconspicuous scales of the rhizome, these 
1.5 to2mm. long, light ferruginous with slightly darker borders, lanceolate to narrowly 
oblong-lanceolate, acuminate, attached just above the rounded base, 7 to 12 cells 
broad in the basal portion, the inner cells acutely elongate, mostly polyhedral, thin- 
walled, 3 to 5 times as long as broad, the outer cells shorter, narrowly oblong, and 
with thicker partition and outer walls; scales provided with 12 to 15 very long slender 
stiff reddish brown spreading bristle-like cilia upon each side and a similar longer 
terminal bristle; stipes slender, 0.3 to 0.4mm. thick, 5 to 15 mm. long, thickly beset 
with slender fragile spreading reddish castaneous hairs about 1.5 mm. long; lamina 
linear, 8 to 14 cm. long, 4 to 6 (rarely 8) mm. broad, pinnatifid at a right angle nearly 
to the rachis, gradually narrower at the short-attenuate lobate apex; segments mono- 
sorous, 40 to 50 pairs, spreading, only the lowermost 1 to 3 pairs smaller, broadly 
triangular, and strongly decurrent, the others oblong to deltoid-oblong, inequilateral, 
short-decurrent, obtuse or subobtuse, slightly apart (or apparently subdistant by 
the curvature of the margins in drying), entire or in larger specimens lightly gibbous 
near the middle; whole lamina strongly long-setose, especially upon the under surface 
(including the rachis), the hairs like those of the stipe; veins obscure, very oblique 
at the base, those of the sterile segments simple or forked, those of the fertile segments 
invariably forked in their basal third, the distal branch terminating in a conspicuous 
hydathode remote from the rounded apex of the segment, the fertile proximal branch 
