SPEAR-SHAPED S PLEENWORT.
A s p l é n i u m l a n c e o l a t u m of Authors.
l o c a l i t i e s .
ExGLiKD . . . Kent, among ivy, on the face of a rock near the High Rocks, and also on the
Hioh Rocks, Tunbridge Wells , Devonshire, Morwell Rocks on the banks of the
Tamar, rocks on the banks of the Tavey opposite Virtuous Lady Mine, rocks
near Cann quarry on the banks of the Plym; Cornwall, near St. Ives, and
various other localities, also the Scilly islands.
W r r .E S ..............M e rio n e th sh ire , n e a r B a rm o u th , on ro c k s a n d w a lls : C aernarvonshire , on a rock
to th e le ft of th e road b etw e en Tan-y-bwlch a n d Aberglaslyn, a n d on a second
rock close to Aberglaslyn,
ScoTL.AND. Î U n k n ow n .
I r e l a n d . S
T h i s is one of our most local fern s; it is confined, as far as
I am aware, to the coasts of Merionethshire, Caernarvonshire,
Devonshire, and Cornwall, and to the neighbourhood of Tunbridge
Wells, where, I am sorry to say, “ owing to the ravages of unprincipled
botanists,” it has become nearly extinct. In Scotland
and Ireland it is at present entirely unknown. I t roots in the
fissures of rocks, and seems to require no depth of e a rth ; in
one instance in the neighbourhood of Barmouth, I have found it
in profusion on an old stone wall. Whenever I have met with
this fern, it has been intermixed with its cognate species,
A. adiantum nigrum, which, in some of its numerous varieties, it
nearly resembles.
The root is black, very long, slender, and penetrating ; in the
fissures of rocks it runs to a great depth ; the rhizoma is brown,
tufted, and densely covered with bristle-like scales; the young
fronds appear in May, arrive at maturity in August, and last uninjured
throughout the winter : they are always fertile.
The form of the frond is various ; in some situations it is of
erect growth, nearly linear, and simply pinnate ; the pinnæ being
stalked and lohed : in this form it produces seed most abundantly,
and the masses, when fully grown, are perfectly circular :
of the three entire fronds represented in the illustration (see the
preceding page), the one to the right is intended for this variety,
and the portions of fronds to the extreme right and left show the
situation of the veins, and mode of fructification : every part of
the frond is perfectly flat, and the entire plant rigid. A second
variety, of pendant growth, and larger size, is lanceolate in form ;
the pinnæ are pinnate, the pinnulæ stalked, serrated, and somewhat
quadrate ; the fronds often reach a foot in length ; they
usually issue from dark holes or shaded spots, and the lower pair
of pinnæ are often weak, bleached, and of small size; the surface
of the frond is generally flat, although sometimes slightly
inclined to concavity, and when this is the case, each pinnula
partakes more or less of the character : the middle frond of the
three represents this variety, and the detached pinnula immediately
adjoining it shows the veins and incipient indusia. A
third variety is of nearly erect growth, but bends over at the
extremity, and the entire frond, together with each individual
pinnula, possesses such a rigid and inflexible convexity, that it is
next to impossible to flatten the plant by pressure : the frond to
the left is intended to represent this form, hut the convexity is
not expressed.
The lateral veins are branched, a branch running to the extremity
of each serrature : the masses of thecæ are attached near
the extremity of the veins, and somewhat alternately, one branch
hearing a mass, and the next being without one : each mass is
at first elongate and linear, and covered by a linear white
indusium ; the indusium afterwards disappears, and the mass
becomes nearly circular.
ÎI