i ; I X I
i: l‘ !
I .
11
l i . L
• r - i , I
• ' i r
I II'
i ' : i
J
M
i f
13S F E R N S O F NORTH AM E R IC A .
from each other by a space equal to their own width. The
texture is chartaceous, and the surfaces, especially the lower
surface, are sparingly chaffy-fibrillose. The margin is entire
and slightly ciliate. The apex is obtuse.
The midveins of the segments are black, prominent on
the lower surface, and slightly depressed on the upper. The
veins are of the same green color as the frond, and are
difficult to see, except by soaking a piece of the frond in
hot water. They diverge from the midvein at an angle of
about sixty degrees, and presently fork into two diverging
veinlets, of which the lower one is slightly curved, and extends
nearly to the margin of the segment, rarely forking again
near the end. The upper veinlet reaches only about half-way
to the margin, and is soriferous at its tip in the fertile fronds.
There are sometimes as many as twenty-four of these forking
veins along each side of the midvein.
The sori are minute, round, and placed at nearly equal
distances from the midvein and the margin. The sporangia
are few to each sorus, and have a ring of fourteen or fifteen
articulations. The spores are yellowish, translucent, ovoid or
reniform in shape, and have a minutely blistered or pustulate
surface. The single vitta along the concave side is sometimes
so broad as to form a kind of wing.
This fern is closely related to P. pecHnatum, which is figured
on our forty-second plate, but on the whole is a smaller
plant, and has more numerous and narrower segments, and
simpler veinlets. The outline of the whole frond is narrower.
i ! !
' I. '■!
F E R N S OF NO R TH AM E R IC A . 139
The two species, as they occur in Florida, may be compared
th u s ;—
p . pec tin atum .
Full-grown fronds two to three feet long,
three to six times longer than broad.
Segments one and a half to three or four
inches long, two to four lines broad,
much dilated on both sides o f the
basc.
Midrib purplish.
Veins dark colored near the base.
Veinlets three or four to each vein.
Sori rather large, often oval.
H a b . — Usually growing in the earth,
often in clayey soil.
P . Plum ula .
Fiill-grown fronds ten to fifteen inches long,
si.x to ten times longer than broad.
Segments one-half to one and a half inches
long, and rarely more than a line
wide, dilated chiefly on the upper
side o f the base.
Midrib black.
Veins greenish at the basc.
Veinlets mostly two from each vein.
Sori small and round.
I I a b . — U sually on living trees, rarely on
fallen logs, or even on the face of
calcareous rock (J. U. S mith).
Miss Reynolds, Dr. Garber and Captain Smith have all
compared the two living plants in their native habitats, and
all agree in considering them distinct species. Captain Smith
writes that P. Plumula, is “ easily distinguished from P. pectinatum
by habit as well as by its place of growth, the pinnæ,
when dry, being strongly involute, even circinate.” The specimens
collected by him growing in banks of red clay and
sand, on the southern shore of Lake Astachula, I refer to
P. pectinatum, chiefly on account of their broader outline and
more numerous veinlets.
From P. taxifolmm, of Linnæus, as this species is understood
by Mr. Baker, P. Plumula differs in having forked
'rl.i
i
i'
li!
. 1 1 ïlil'i
a
V
f ¡1