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to the apex of the frond. The sterile pinnæ are pinnatifid,
while the fertile ones are pinnate, the usually distant pinnules
being oblong, obtuse, slightly toothed, and adnate to a narrowly
winged secondary rachis, or the lower ones supported
on a short and wing-margined stalk.
The sori are rather large, and are placed about midway
between the midvein and the margin. The indusium is round-
reniform, perfectly smooth, and rather rigid. The spores are
dark-brown, bean-shaped and very rough on the surface.
The manifest relationship of this fern is to A . cristatum,
a form of which I formerly considered it, and I am by no
means sure that- this opinion is not correct. It has a similar
root-stock, similar scales and closely similar sterile fronds;
and it is only in the fertile portion of the fruiting fronds
that any considerable difference appears.
A . Floridanum proves hardy in the botanical garden at
Cambridge, and, as seen there, its resemblance to A . cristatum
is greater than in herbarium specimens from Florida.
A . Ludovicianum is unknown to me. It was placed in
§ Polystickum by Kunze.
The plate represents a fertile frond with the root-stock, collected
near Fernandina, Florida, by Mr. C. E. Faxon. Fig. 2 is a fertile pinnule,
enlarged. Fig. 3 is an indusium; Fig. 4, a spore; and Fig. 5,
a section of the stalk.
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