598 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
walls reddish brown, moderately sclerotic, the outer cell walls hyaline or 
_lutescent), copiously ciliate (chiefly above the middle), the cilia 0.15 to 
0.38 mm. long, bristle-like, hyaline; stipe 1.5 to 2.5 em. long, 0.8 mm. in 
diameter, pale brown, terete, minutely pubescent; lamina 14 to 24 em. long, 
8 to 12 em. broad, oblong, acutish at the apex, essentially pinnate, very abruptly 
expanded above the base, the extreme basal portion consisting of a few alternate 
sinuately joined lobes or low crenations; rachis slender, blackish, slightly 
elevated, subflexuous toward the apex, glabrescent; principal segments 15 to 17 
pairs, spreading (70°), alternate, mostly straight, 4 to 6.5 em, long, 3 to 5 mm. 
broad, linear-attenuate, acutish, lightly sinuate, slightly dilatate above, strongly 
so below, 10 to 11 mm. broad at the rachis, the segments here contiguous but 
scarcely at all connected (the sinus wide, inequilateral, obliquely acutish), 
elsewhere 1 to 3 times their width apart; midvein subflexuous, nearly tm- 
mersed ; veins 12 to 22 pairs, arising at an angle of about 40°, simple, the sterile 
ones straight, the fertile ones sharply geniculate nearly at a right angle from 
the proximal side of the protruding receptacle; sori 7 to 14 pairs, slightly 
supramedial in attachment, deeply impressed, apart, equidistant from the mid- 
vein and margin; sporangia glabrous, the annulus 12-celled. Leaf tissue dark 
green, glabrous, rigidly subspongiose-herbaceous, semitranslucent, pustulate over 
the sori. 
Type in the U. 8S. National Herbarium, no. 675858, collected from a tree trunk 
in humid forest between Alto de las Palmas and top of Cerro de la Horqueta, 
Chiriquf, Panama, altitude 2,100 to 2,268 meters, March 18, 1911, by William R. 
Maxon (no. 5478). . 
Polypodium chiricanum, which is known only from the type specimen, is a 
near ally of P. subsessile Baker, differing from that species especially in its 
greater size, its broader, scarcely clathrate, longer-ciliate rhizome scales (these 
brownish and not at all grayish in mass), its longer, broader, and strongly de- 
current (not subequally dilatate) segments, nearly immersed midveins, and 
more acutely divergent veins. 
EXPLANATION OF PLATE 43.—Type specimen of Polypodium chiricanum. Scale }. 
Polypodium crassulum Maxon, sp. nov. 
Plants epiphytic, the fronds pendent, several to very numerous, imbricate- 
fasciculate, long-persistent, 20 to 40 cm. long. Rhizome stout, erect, 2 to 5 cm. 
long, nearly 1 cm. in diameter, copiously and coarsely radicose, only the apex 
paleaceous, the scales concealed, reddish brown in mass, 2 to 3 mm. long, 0.15 to 
0.25 mm. broad, linear, entire, semitranslucent, yellowish brown singly, con- 
colorous, both outer and partition cell walls thin; stipe 1 to 5 cm. long, sub- 
terete, gradually flattish above, very copiously tomentose-pilose, the close-set 
spreading hairs reddish brown, very slender, 3 to 5 mm. long; lamina 18 to 38 
em. long, 5 to 8 em. broad, linear, acuminate at the apex, acute at the base, sub- 
pinnate, often more or less irregular in outline from the abortion of the apex 
and of the segments; rachis flexuous, wholly immersed ; segments 20 to 50 pairs, 
oblique (60°), 3 to 8 cm. long, 2 to 2.5 mm. broad, linear, long-attenuate, entire 
or slightly sinuate, fully adnate but not surcurrent, long-decurrent and faintly 
connected, elsewhere 1 to 3 times their width apart; segments sometimes once 
or twice dichotomous in their outer part; midvein immersed, medial, decurved 
at the base; veins 10 to 20 pairs, immersed, borne at an angle of 10° to 30°, 
simple or mostly once forked, the proximal branch greatly extended; sori rather 
few and intermittent, 3 to 8 pairs, nearly superficial, terminal upon the vein or 
at the clavate end of the proximal branch, touching or exceeding the margin, 
paraphysate; sporangia glabrous, the annulus 11 or 12-celled. Leaf tissue rig- 
