Thelypteris nigrescentia (Jenman) C.F.Reed

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POLYPODIUM (GONIOPTERIS) NIG UK-j-
CENTIUM, Jenm. n. sp*
Native of Jamaica, among the lower bills, in St.
Mary parish. Intermediate between crenatam and
obliteratum in its general character!. Its charac-
teristic features are the relatively strong rootstock,
small densely-grouped fronds, repand and crinkled,
▼ery slightly cut pinnae, and copious sori. As a rule,
the terminal segment is shortened, which gives the
fronds an oblong quadratiform aspect that is very
characteristic. As in all the allied species, in the
very early stage of the sori, a rudimentary trace,
often of hardly more substance than a film, of an
involucre can be detected with a good lens. It
would be more natural to leave these species pos-
sessing reniform sori in Aspidium, the presence or
apparent absence of an involucre, especially in dried
specimens, being very misleading. I have a frond
of the truest of true P. crenatum, Sw„ gathered in
Jamaica, which, instead of being nude, has invo-
lucres as ample in their degree at a woman’s skirt*.
I Or. S. Jtiiman, Demerara, June, 1894.
* Polypodium (Goniopteris) nigreicentium, Jenm., n. sp.—
Rootstock strong, stout, decumbent or oblique, shortly repent,
dark, scurfy, clothed with a few minute dark-brown scales;
stipites more or less freely tufted, erect, 3 to 7 inches long,
slightly cnannelled, puberulous, with a few minute dark-brown
scales at the base; fronds erect, pinnate, subooriaceous, dark-
green, glossy, pellucid, glabrous, the rachis brown-puberulous,
3 to 5 inches long, 2 to 4 inches in breadth, composed of three
to seven spreading, sessile, oblong-lanceolate acuminate pinnae
and a similar terminal one, which are to 3 inches long, J to
£ inch wide, the upper ones truncate, the lower rounded or
sub-cuneate, and not reduced, repand, the margins slightly
lobed or serrulate-crenate; veins four to five to a side, the i
opposite ones connecting at an angle with an intermediary j
that runs to the sinus, and very pellucid at the top; sori '
copious, oocupying all but the exterior veins, and covering i
most of the surface-. A
THE NEW YORK BOTANICAL GARDEN
Herbarium of George S. Jenman
PRESENTED BY MR. D. O. MILL8, 1903
JAMAICA
NEW YORK BOTANICAL GARDEN
01905523
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