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W il ld en ow , Sp. PI., v., p. 336. — P u r sh , FI. Am. Sept., ii.,
p. 667.— B ig e low , FI. Boston., ed. iii., p. 4 2 2 . T o r r e y , FI.
New York, ii., p. 4 9 3 .— G r a y , Manual, ed. i., p. 627, e tc.—
M e t t e n iu s , Fil. Hort. Lips., p. 78 ; Asplenium, p. 184. — E a to n ,
in Chapman’s Flora, p. 593. — H o o k e r , Sp. Fil., iii., p. 229.—
H o o k e r & B a k e r , Syn. Fil., p. 226. — L awson, in Canad. Naturalist,
1864, p. 276. — W il l iam so n , Ferns of Kentucky, p. 71,
t. xxii. — D a v en po r t , Catak, p. 24.
Asplenium acrostichoides, S w a r t z , “ in Schraders Journ., 18 0 0 , ii., p. 54;"—
Syn. Fil., p. 82, 275.
Athyrium thelypteroides, D e s v a u x , “ Prodr. p. 266." — F é e , Gen. Fii.,
p. 186. — M o o r e , Index, p. 188.
Diplazium thelypteroides, P r e s l , Tent. Pterid., p . 1 1 4 .
H a b . — Deep rich woods; not rare from New Brunswick and Canada
to Central Alabama, and westward to Wisconsin. Also in Penang,
the Himalayas, and in Amur-land.
D e s c r i p t i o n : — This is one of the more conspicuous
ferns in the forests of the Northern States, and is most
frequently found where a rivulet trickles through deep forests
on the lower slopes of a mountain, keeping the earth at all
times moist. The root-stock is several inches long, and creeps
just beneath the surface of the ground, the advancing end
bearing a crown of large and deep-green lustreless fronds,
and the older part bearing the up-curvcd and adherent bases
of former stalks. It is covered with branched and entangled
rootlets, but bears little or no chaff, differing in this respect
from the otherwise somewhat similar root-stocks of several
of our common species of Aspidium.
I ff
35
The stalk, though chaffy when very young, is when
mature nearly smooth, and is stramineous when dry. It is
furrowed on the anterior side and contains two flattened
fibro-vascular bundles.
The fronds are herbaceous, rather thin in texture, and
wither at the first touch of frost. They are commonly
about two feet long, exclusive of stalk, and one-fourth as
rvide in the middle. Towards the base they are moderately
contracted, sometimes much contracted, and they taper
to. a slender apex. The pinnæ of a large frond are five or
S IX inches long, and rarely as much as an inch wide. They
are attached to the rachis by so short a stalk as to be almost
sessile, and spread obliquely, or are even slightly decurved,
as in A s fid ium Thelypteris, from its resemblance to
which fern the present one was named. The lower pinnæ
are much more widely separated than the middle and upper
ones, as is the case in most pinnated ferns. The pinnæ
are cut into numerous oblong lobes, the incisions extending
to within half or three-fourths of a line of the midrib.
Usually the pinnules are but slightly toothed, but Dr. Lawson
has described in the Canadian Naturalist a var. serra-
Imn, with the “ lobes of the pinnæ ovate-oblong, approximate,
strongly and incisely serrate." The veins diverge obliquely
from the midvein, and are simple, running nearly straight to
the margin. Sterile fronds have rather wider pinnæ and lobes
than the fertile ones; in the latter all, or all but a very few, of
the lowest pinnæ arc well covered with fruit.
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