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136 F E R N S O F NORTH AM E R IC A .
Polypodunn elasticum, “ R ic h a rd ;" Baker, Syn. Fil., ed. ii., p. 332.
rolypodhim pidchrum, M artens & G aleotti, Syn. Fil., Mex., p. 4 1, t.
8, Fig. 2. (This is kept distinct by Fournier, who has seen
the original specimens, but is referred to P. elasticum by
Baker. Fournier gives several synonymes o f P. Plztmula,
which I have been unable to verify.)
H ab. — Almost always on the trunks of living trees, the rootstocks
covered with mosses and lichens. Tampa Bay. Dr. M. C. L e .av-
enworth. Near Enterprise, Mr. C. E . Faxon. Indian River, Mr.
W hitney. Fourteen miles west of St. Augustine, Miss R eynolds.
Along the Corkscrew River, D r. Garber. Near Lake Astachula, Captain
J . D onnell Smith. Mexico to Venezuela and Brazil.
D e s c r i p t iOxN : — The root-stock is about two lines in diameter,
and rarely over two inches long. The growing end
and the bases of the stalks are covered with dark-brown
lanceolate slender-pointed scales, destitute of midnerve, and
obscurely ciliate-toothed. The stalks grow in a double row
from the upper side of the root-stock, and, when fallen away,
leave little raised concave scars on the root-stock, being articulated
at the base, as are all the true Polypodia. The
stalks are fuscous-black, terete, rigid, about two-thirds of a
line thick and four inches long in the largest plants, and much
slenderer and shorter in plants of smaller growth. A section
shows the outer sheath of hard tissue to be very thick and
firm, and discloses a central somewhat triangular fibro-vascular
bundle. A very slight herbaceous line extends down each
side of the stalk for some little distance below the lowest
F E R N S OF NORTH AM E R IC A . 137
segments. In young fronds the stalk and the midrib are
ferruginous-puberulent and sparingly paleaceous, but older
ones become gradually smoother; more or less of this roughness,
however, adheres permanently to the midrib.
The fronds are narrowly linear-lanceolate in outline, and
are gradually contracted towards both base and apex. The
lowest segments are distinct, and do not pass into mere enlargements
of the descending herbaceous lines. The frond
terminates in an apical segment, which is seldom so long as
- to be fairly caudate. The ratio of the length of the fronds
to their breadth is usually about ten to one, but is sometimes
as low as six to one. The fronds are nearly erect
when fresh; but when dry from the heat of the sun, or
when dried for preservation, they show a very decided curvature,
either backwards or to one side; at the same time the
segments coil up nearly to the midrib, showing only the
under surface. This habit is plainly seen in the specimens
gathered by Captain Smith, and is commented on by Miss
Reynolds in her article in the Botanical Gazette. When
moistened again the curvatures disappear, just as the infolding
of the segments of Polypodium incanum disappears when the
dried fronds of that fern are moistened.
The segments are very numerous, a frond fifteen inches
long having over ninety of them on each side. They are
rarely over a line wide for most of their length, but at the
base are dilated, on the upper side especially, to nearly twice
that width. They are thus, except near the midrib, separated
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