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162 FERNS OF NORTH AMERICA.
Pterid., p. 82. — F é e , Gen. Fil., p. 2 78 .— G r a y , Manual, ed. i.,
p. 632. — M oo r e , Nat. Print. Brit. Ferns, t. ix. — R u p r e ch t , Dist.
Crypt. Vase. Imp. Ross., p. 3 8 .— W. D. W h it n e y , in Foster &
Whitney’s Rep. on Geol. of L. Superior, part ii., p. 380.
H a b . — Rocky places, from the vicinity of Georgian Bay, Lake
Huron, Canada, Professor H incics, Mi's. R o y , Mr. W a i t , to the southern
shore of Lake Superior, Professor W h it n e y , etc., and westward to the
Cascade Mountains of British Columbia, Dr. L y a l l . Southward it occurs
along the mountains as far as Utah, having been found in the Wahsatcli
Mountains by Mr. W a tson , and near Spring Lake by Dr. P a r r y . Northward
it extends to Unalaska and Greenland ; and in the Old World it
occurs in alpine and sub-alpine regions from the British Islands to the
Caucasus, and from Spain to Lapland and Siberia. Dr. Milde gives Labrador
also, but I know not on whose authority.
D e s c r i p t i o n . — The holly-fern has a thick and almost
woody root-stock, closely covered with the imbricating bases of
former stalks. The newer portion is very chaffy, with ample
ovate rusty-brown scales. The fronds stand in a crown at the
top of the root-stock, and are nearly sessile, or at most have
stalks only four or five inches long. These stalks bear copious
large chaffy scales, mixed in with much smaller and narrower
scales : the latter are seen in greater or less abundance along the
rachis also. The fronds vary in length from a few inches to two
and a half feet, and in width from less than an inch to two inches
and a half. In outline they are narrowly lanceolate, the greatest
width being above the middle of the frond, so that they are
gradually narrowed downwards for more than half their length.
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FERNS OF NORTH AMERICA. 163
The apex is acute or shortly acuminate. The pinnæ are closely
placed, and very numerous, a frond of average size having as
many as fifty on each side of the rachis. The lower pinnæ are
triangular, having the upper and lower sides nearly equal, and
slightly auricled. Higher up the frond, as the pinnæ become
longer, the inferior auricle disappears, and presently the lower
side of the pinnæ is narrowed at the base, while the auricle on
the upper side is more developed, and at the same time the pinnæ
are strongly curved upwards. The edges of the pinnæ are serrate,
having large spinulose-poiiited teeth, with much smaller
pointless teeth interposed between them. The veins are free,
and proceed from a midvein. The fronds are rather rigid, sub-
coriaceous in texture, and evergreen. The upper surface is
smooth, but the under surface is more or less chaffy. The
fruit-dots, which are confined to the upper portion of the frond,
are usually arranged in a single row each side of the midvein,
and about half way between it and the margin : they also occur
on the auricles in two similar rows.
The indusium is orbicular and nearly entire, and attached
by the centre to a short stem which rises from the middle of
the fruit-dot. As the sporangia mature, the indusium contracts
a little at the margin, and becomes somewhat funnel-shaped.
The spores are ovoid-bean-shaped, and have a minutely muricu-
late surface.
The holly-fern is singularly free from variation ; the only
differences noticed being of size, and of coarser or finer serration.
It belongs to the same group of species as A . acrosti-
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