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52 FERNS OF NORTH AMERICA.
of sixty degrees ; but more frequently they spread out nearly at
right angles with it. The lower pinnæ are gradually more distant
than the middle ones, and are shorter and more deflexed towards
tlie base of the frond, so that the very lowest ones are often not
more than two lines long. The lobes or segments of the pinnæ
are flat, slightly oblique, oblong, rounded-obtuse, and entire or
slightly toothed. The lowest segments of each pinna arise from
the very base of its midrib, so that the pinnæ are absolutely
sessile on the main rachis. These lowest segments are sometimes
a little shorter than the higher ones ; but in other specimens
they arc found rather larger than th.e rest, and more decidedly
toothed.
The venation is free : each lobe has a central mid-vein, and
on each side of this about six or seven pinnately arranged veinlets.
These leave the mid-vein at an angle of about forty-five
degrees, and run straight to the margin of the lobes. They are
normally simple ; but in fronds with enlarged and toothed basal
lobes they are sometimes forked, or the lowest vein of several
lobes may be forked. The texture of the fronds is thin, so that
they wither quickly when gathered, and die at the first approach
of cold weather. The rachis, midribs, veins and veinlets, especially
along the lower surface of the frond, are minutely pubescent
with straight whitish hairs, and the lobes are ciliate with hairs of
the same kind.
The sori or fruit-dots are much smaller than they are in
some of the other common Aspidia. They are seated one on the
back of each veinlet, nearer the margin of the lobe than the mid-
FERNS OF NORTH AMERICA. 53
rib, and are almost always distinct. The fruit, when it is present
at all, usually occupies the whole of the fruiting frond, which, as
in most ferns, is rather narrower than the sterile frond, and has
narrower divisions. The indusia are reniform and attached by
the sinus, and very delicate. The cellules are irregular in shape,
and may be called roundish-polygonal. The margin is bordered
with minute yellowish globules, or glands ; and sometimes a few
occur on the surface also. Besides the glands, the indusia often
bear a few short and straight whitish hairs. Schkuhr’s figure,
quoted above, gives an excellent representation of the indusium.
The spores are ovoid-reniform, very much the shape of a kidncy-
bean, but with a muricate surface and more or less of a semitransparent
border or wing along the slightly hollowed side.
The sweet-scented variety has been noticed by Mrs. Millington
for several successive years. It differs little from the common
form. The specimens sent me are narrower and more rigid.
The glands with which they are sprinkled on the under surface
are nearly black in the dried plant, and the indusium is more permanent.
Mrs. Millington writes that “ a few plants dried in the
open air will perfume a room deliciously for a long time.” My
specimens, gathered in 1873, are still pleasantly fragrant.
This fern has been confused at times with Aspidium Thelypteris.
In the “ Flora Boreali-Americana” S ir W. J . Hooker
united the two; and many years later, in writing the account of
this species for the “ Species Filicum,” he appears to have still
entertained doubts as to its distinctness. But the only specimens
in his herbarium at that time were imperfect fronds from Canada,
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