40
Vi!
i'V
. 1:
iii
Tlie preceding forms, particularly fig. h in page 39, have
prepared the reader for the lonchitiform or simply pinnate
variety of this variable plant. In the Smithian Herbarium is a
frond, the aculeatum, ¡3. of the English Flora, which was found
on the Welsh mountains, and of which the pinnæ
are nearly as entire as in the accompanying cut,
and of this Sir J. E. Smith says, “ it is sometimes
taken for A. Lonchitis.” The fronds represented
in the margin (fig. i) were found by myself
at Twll-du in Caernarvonshire ; they were
apparently the growth of 1837, although
obtained in 1838, and the rhizoma was
^actually producing young fronds, divided
as in lobatum ; in cultivation this plant
has produced the lobatum form only.
I The veins of course vary greatly in
accordance with the divisions of the
frond; they are always unconnected with
each other at the extremity, a character
which separates this genus from Aspi-
dium. In the pinna in the annexed cut
the lateral veins are three-branched ; of
these the anterior branch hears a mass
of thecæ near its extremity, and is not
continued like the others to the margin
of the pinna. The indusium is orbicular,
scale-like, and attached by a stalk in
the centre ; it shrivels, decreases, and
falls off or disappears in the centre,
as the thecæ approach maturity: the
masses of thecæ are circular and rarely
confluent : they occur only on the upper
part of the frond.
I have carefully compared the frond
from which fig. i is drawn with the two
specimens of Polypodium Lonchitis in the Linnean Herbarium,
and I am totally unable to detect any difference between them ;
I am therefore of tlie opinion that had the plant from which
these fronds were gathered been transplanted to a hedge-row
in which its roots could reach abundance of decaying wood, that
it would speedily have become broken into lobatum, and before
many years into angulare.
Although our botanists have named four forms of this
fern, I believe there are hut three which will he generally
understood; all these I would consider as constituting but a
single species, to which I would assign the Linnean name of
aculeatum, and call the different forms merely varieties,
thus :—
Var. 1.—Angular type. Frond doubly pinnate; pinnulæ
ovate, hluntish, stalked and auricled at the base ; the whole
plant light, feathery, graceful, and extremely flexible : this form
is figured at page 37.
Var. 2.—Lohate type. Frond doubly pinnate ; pinnulæ
pointed, decurrent, serrated, the foremost of the lower pair on
each pinna very large and pointing towards the apex of the
frond ; the whole plant rigid, heavy, compact, and unbending ;
grows in general horizontally : this form is figured at page 39.
Var. 3.—Lonchitiform type. Frond simply pinnate ; pinnæ
stalked, undivided, prickly; habit weak, flexible, pendulous:
this form is figured at page 40.
Mr. Francis has figured all the varieties of this plant as having
the reniform fructification of the genus Lastræa. Fig. 1, 2, and 4,
plate 2, belong to the lohate type of the above list ; figs. 1 and 4
correspond with my figure /,- figs. 3 and 5 of Francis belong to
the angular type.
As many of our botanists will be inclined to smile at my
attempt to blend together species which they have been accustomed
to consider as perfectly distinct, I will mention that since
the publication of my remarks in the Magazine of Natural
History, I have received various written communications on the
subject, some of them from botanists who in some degree
participate in my views ; for instance, the following from Mr.
C. C. Babington. “ I am inclined to consider lobatum,
aculeatum, and angulare, as forms of one species ; many intermediate
states occur in which it is quite impossible to say to
which of the supposed species they ought to be referred ; some