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22 FERNS OF NORTH AMERICA.
to Indian Territory (Dr. E dwa rd P a lm e r ) and Louisiana. It is found
commonly on sunny or partially-shaded rocky hillsides, but occurs not unfre-
quently in moister places. The sporangia mature in midsummer or early
autumn.
D e s c r i p t io n . — The ebony spleenwort, so called from the
nearly black and shining stalks and rachis, has a short and rather
stout creeping or ascending root-stock, which is covered by the
bases of old stalks. The stalks are seldom more than two inches
long ; they are nearly terete, and contain a single slender vascular
bundle. The young stalks, and the very bases of the mature
ones, bear a few narrow, slender-pointed, black-fuscoys scales,
composed of thick-walled, oblong-rectangular cells arranged in
longitudinal rows, looking under the microscope like some kind
of lattice-work. The fronds are usually six or eight in number,
and stand nearly erect, but commonly all facing towards the light,
some of them making a twist to do so. They are firmly membranaceous
in texture, quite smooth, and remain green until late
in the fall, or even in favorable places until the spring. The
earliest fronds of each season’s growth are sterile, and much
shorter than the later fertile ones, which are commonly from six
to twelve inches high, but sometimes in moist situations attain
twice that height. The outline of the fronds is linear, tapering
gradually to the base from near the middle, and with an acute
pinnatifid apex. The pinnæ are sessile and closely placed, often
overlapping each other a little at the dilated and somewhat auricled
bases. The auricles are commonly most developed on the
superior margin ; but not unfrequently the lower margin is almost
as much auricled as tlie other, making the bases of the pinnæ
cordate-hastate, so that they nearly cover the upper side of the
rachis. On any frond of ordinary size there will be found about
forty piimæ, — the middle ones eight to ten lines long and about
two lines broad, spreading at right angles to the rachis, often sub-
falcate ; the lower ones gradually shorter, more and more deflexcd,
and the auricles on each side of the base more nearly equal ; the
very lowest only two or three lines long. The margin is commonly
serrate ; in very small plants barely crenate, and in luxuriant
ones incised, with serrated lobes. There is a well-marked
mid-vein or costa, with simple or branched veins pinnately
arranged on either side. The sori, from eight to fifteen in number,
are borne near the costa, always leaving uncovered the green
herbaceous margins of the pinnæ. The indusia are very delicate,
three or four times as long as they are broad ; and when the
frond is young they give to the under surface a bright silvery
appearance.
The name “ var. serratum" has been proposed by Mr. Elihu
Miller (Torrey Bot. Club Bull., iv., p. 41) for the large form with
incised pinnæ ; but the normal condition of the pinnæ is to be
serrate.
This fern is said to have been found in South Africa also ;
but I have not seen specimens from that region.
Var. mmus (Hooker, Sp. Fil., 1. c.), which is found from Tennessee
to Mexico and Peru, will be described in a later number
of this work under the name of Asplenium parvulum (Martens
and Galeotti). To this plant belongs the A . trichoma7toides