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of the frond; of the former, toward the costa. In the areoles of
the second series the sori are opposite ; the indusium of the lower
one free toward the costa; of the other, in the opposite direction.”
To this it may be added, that in some of the areoles the two sori
meet and are confluent at the outer angle of the areole ; and in
this case the two indusia are sometimes, though not always,
united into one. The indusia of the areoles next the midrib are
also often bent at an angle, and the two portions plainly united.
It was from this condition of some of the sori that the genus was
named Camptosorus (bent fruit-dot) ; and it is only on this peculiarity
that the genus can be kept separate.
The indusium is thin and delicate, composed of sinuous-
margined cellules, and is more or less wavy along the free edge.
The spores are ovoid, and have a crenated pellucid wing-like
margin.
Sir W. J. Hooker referred the Camptosorus, together with
the species of Antigramma, and the very peculiar Mexican fern
Schaffîieria, to the genus Scolopeiidrium ; making the distinctive
character of the genus to rest on the sori being “ in pairs, opposite
to each other, one originating on the superior side of a veinlet,
the other on the inferior side of the opposite veinlet or
branch.” In this he was essentially anticipated twenty years by
Dr. Endlicher ; to whom, however, Schaffneria was unknown.
It is by no means impossible that future botanists will refer
all these species to the old Linnæan genus Asplenium ; for it is
now pretty generally admitted that differences in venation do not
constitute valid generic distinctions, and a radicant bud on the
frond is common in many undeniably genuine A sp len ia : and
since Diplazimn, with double involucres placed back to back on
the same vein, is inseparable from Asplenium, it is by no means
impossible that Scolopendrium and Camptosorus should be thought
to have no better claim to rank as genera.
Probably the earliest notice of the walking-leaf is in R a y ’s
“ Historia Plantarum,” vol. ii., p. 1927, published in 1688. It is
there called “ Phyllitis parva saxatilis per summitates folii prolifera.”
Other early accounts may be found in the “ Species
Plantarum ” of L in n æ u s and of W i l l d e n o w , and in the second
edition of G r o n o v iu s ’s “ Flora Virginica.” In the latter work it
may be seen that Gov. Golden long ago described the auricles
as being “ also often acuminate.”
A second species, with membranaceous fronds acute at the
base (C. Sibiricus), occurs in Northern Asia, but is apparently
very rare.
Plate V III., Fig. I .— Camptosorus rhizophyllus. The specimens are
of the form with acuminate auricles. A portion of a frond with rounded
auricles is drawn about twice the natural size, to show the peculiar arrangement
of the veins and sori.
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