14 T. J. W. BURGESS ON RECENT 
eight inches of the total twenty-four. The fronds, rather narrowly oblong-lanceolate in 
general outline, are gracefully acuminate, and have all the pinne densely soriferous, the 
lower ones being distant and considerably decreased in size. 
Genus XIV.—ASPIDIUM, Swz. 
2a,—A. OREOPTERIS, Swz., (Mountain Shield-Fern), Syn. Fil., 50. Willdenow, Sp. PI, 
V, 247. Eaton, Ferns of N. À. II, 273. Underwood, Our Nat. Ferns, etc., 105. 
A. montanum, Milde, Fil. Eur. et Atlant., 115. 
A. odoriferum, Gray. 
Polypodium fragrans, L. 
Polypodium montanum, Vogler. 
Polypodium pterioides, Villars. 
Polypodium limbospermum, Bellardi. 
Polypodium oreopteris, Ehrh. 
Polypodium thelypteris, Bolton. 
Polystichum montanum, Roth. 
Lastrea oreopteris, Presl. 
Lastrea montana, Moore. 
Hemestheum montanum, Newman. 
Nephrodium oreopteris, Desvaux. 
Nephrodium montanum, Baker. 
This is a rich, golden-green, handsome, though rather stiff-looking species, found 
growing in patches, usually in open wet ground, in ravines and on mountain slopes, and 
varying in height from one to three feet. Rootstock short, stout, erect or ascending, chaffy, 
and covered with old stalk-bases; stalks short, generally forming about one-fifth or less 
of the height of the plant, somewhat chaffy especially at the base; fronds erect, firmly 
membranaceous, glandular beneath, commonly with some scattered chaff along the rachis, 
ten to thirty inches long, lanceolate in outline, acute, tapering from near the middle to a 
narrow base, pinnate; pinnæ sessile from a broad base and deeply pinnatifid, the middle 
ones lanceolate-acuminate and two to five inches long, gradually reduced to the lowest, 
which are deltoid, one-third to one inch long and slightly but increasingly distant; pin- 
nules numerous, oblong, obtuse, entire or slightly crenulate, and, like A. thelypteris, their 
margins sometimes revolute so as to give them the appearance of being acute; veins free, 
often forked; sori near the margin; indusia very delicate, more or less toothed at the 
margin, fugacious. 
This fern approaches more closely to A. fhelypteris than to any other of our Canadian 
species, but is readily separated, both from it and from A. Noveboracense, by its tufted, not 
creeping, rootstocks. In the absence of root, the most obvious distinguishing characteris- 
tics are that, in the former, the stalks are long, the fronds are rarely narrowed at the base, 
the veins are nearly all forked, and the sori are not marginal; while in the latter, the 
fronds are thin-membranaceous, minutely ciliate and hairy, and the veins are almost always 
simple. Of North American species as a whole, however, A. oreopteris finds its closest 
ally in the Californian A. Nevadense, Eaton. The rootstocks are alike, and both are nar- 
rowed to the base, but as a rule, the former is a coarse, rigid fern, and the latter is slen- 
