688 SLOSSON: NEW FERNS FROM TROPICAL AMERICA 
not likely to be mistaken for any other. Marked by its bright 
shining green color, rounded, undulate or not more than sublobate 
margins, and few flabellately forked veins tapering toward the 
apex. From Trichomanes sphenoides Kunze, which also has fla- 
bellately forked veins tapering toward the apex, it may be easily 
distinguished by the greater distance between the tips of the true 
veins, varying from .5 to 2 or 2.5 mm., and by the very thick 
walls of the cells of the laminae. 
Polystichum machaerophyilum Slosson sp. nov. 
Rhizome erect, its scales light brown, 2.5-6 mm. long, ovate 
to oblong, fimbriate or subfimbriate; scales of lower part of the 
stipes similar, passing into minute scales scattered over both sur- 
faces of the frond, which are elongate-caudate, entire or slightly 
toothed, from a short more or less fimbriate-ciliate base; fronds 
up to 51 cm. long, up to 7.1 cm. broad; stipes 2.5-20.5 cm. long, 
brownish-stramineous or greenish, channeled on the face, rounded 
at the back, the upper part channeled also or flattened on the 
sides; rachis similar to upper part of the stipe; laminae brownish 
olive, lanceolate or lance-linear, slightly tapering toward base, 
pinnate, the apex in young fronds often deltoid-acuminate, in 
mature fronds of two kinds, the first subcaudate, elongate-linear 
or lanceolate, subentire or undulate or serrate-lobate, often pro- 
liferous at tip, the second flagelliform and proliferous at tip, naked 
or with a few small scattered pinnae, both kinds sometimes on 
the same frond, the second terminating the first; pinnae mostly 
alternate, 8-27 to a side, usually approximate or distant, the lower 
short-stalked, the upper sessile or subsessile or adnate, often 
passing into short variously shaped often obovate segments, 
principal pinnae broadly cuneate-hastate, above the auricles 
deltoid to linear, the basal margins entire, the outer margin sub- 
entire or undulate or with one or more minute occasionally spines- 
cent teeth or in large fronds irregularly crenately lobed, the lobes 
sometimes mucronate, basal auricles and apex of pinnae spinescent; 
texture coriaceous-chartaceous; venation pinnate, obscure, veins 
very oblique, about 1-4 times forked, the basal auricles with 
distinct midveins; sori usually about midway between the midvein 
and the margin of the frond, or nearer the midvein, rarely a few 
submarginal; indusia more or less erose or with a few cilia; spo- 
rangia glabrous; spores cristate. 
Type in the Underwood Herbarium at the New York Botanical 
Garden, collected at Arroyo del Medio, above the falls, Sierra 
