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2 . FERNS OF NORTH AMERICA.
D e s c r i p t io n . — The climbing-fern, creeping-fern, Hartford-
fern, or Windsor-fern-, as it is variously called, has a long and
very slender root-stock, scarcely one line in diameter. This root-
stock creeps just under the surface of the ground to a distance
of several inches, or nearly a foot, in one season. The growing
extremity of it is scantily furnished with short, semi-pellucid
jointed hairs. The root-stock is of a very dark brown color,
almost black : it bears on the under side short, straggling roots ;
and from the upper side, some distance from the newest portion,
arise, at a distance apart of one or two inches, the delicate climbing
fronds. The stalk or stipe is dark at the base, but at a few
inches above the ground becomes paler : in the growing plant it
is greenish, but becomes of a dull brownish straw.color when
dried. It is very slender, — not more than half a line in thickness,
— and yet has considerable strength. A transverse section
is roundish triangular ; all the outer part composed of dark brown,
firm, thick-walled wood-cells, while in the centre is seen a small
circular portion of scalariform ducts and parenchyma. The fronds
creep and climb and twine themselves over other plants to the
height of three or four feet, or even more. The sterile fronds are
strictly bipinnate, and so also is the lower part of the fertile fronds.
Beginning at six or eight inches from the ground, the twining
midrib or rachis bears very short branches one or two inches
apart. These branches divide, at about one-eighth of an inch
from the midrib, into two slender petioles something less than
an inch long, and each petiole supports at its end a kidney-shaped,
deeply-lobed leaflet or pinna. These pinnæ are usually about an
FERNS OF NORTH AMERICA.
inch and a half broad, having a decply-rounded sinus at the base,
and are palmately cleft into from four to seven, rarely more,
oblong or linear-oblong, entire or obscurely-crenulate, obtuse lobes.
The veining resembles slightly the branching of our common
maiden-hair. From the base of the leaflet arise two veins, which
diverge, and are recurved to right and left. These bear, on the
upper side, â few straightish primary branches, each forming the
mid-vein of a lobe of the leaflet. From each mid-vein veinlets
arise very obliquely, forking usually twice, and gradually curve
outward to the edge of the lobes.
The texture of the pinnæ is rather delicate, — what maybe
called papyraceo-herbaceous, — and the color is a fine, clear leaf-
green. The surfaces seem to be smooth, though a few scattered
hairs have been detected along the veinlets on the under surface.
In the fruiting-fronds, several of the uppermost pairs of leaflets
are paniculately decompound, being bipinnately divided, the pinnules
usually three-lobed or three-cleft, but sometimes two-to-five-
cleft. The lobes are about two lines long, half a line broad, and
have one central vein, along each side of which, on the under
surface, is a row of four to eight convejc ovate imbricating scales,
or involucres, each one affixed to the upper side of a very short
lateral branch of the central vein, to which branch, under each
involucre, is attached a single obliquely-ovate reticulated capsule
or sporangium. The sporangia are comparatively large, and have
at the smaller end a sort of radiated cap, which is homologous
with the incomplete vertical ring of the sporangia in such ferns
as Polypodium and Aspidium. These sporangia open by a Ion