Il
BLACK S PLEENWORT.
A s p l é n i u m a d i a n t u m - n i g r u m of Authors.
A spleniurn lucidum.—Oray.
L O C A L IT IE S .
E n g la n d .
Wa l e s . I
Sco t la nd, f
I r e l a n d , j
Universally distributed.
T h e Black Spleenwort is more or less abundant in all our
counties: its natural habitat, like that of A. lanceolatum,
appears to he the fissures of barren and exposed rocks, hut in
these situations it never attains the size or luxuriance which it
so constantly exhibits when growing on our walls, on ruins, or
in our hedgerows.
The root is very black and wiry ; the rhizoma tufted, black,
and covered with bristly scales; the rachis is extremely smooth and
shining, having a few scattered scales at its base; one-third of
its entire length is naked, and this portion is usually black, or
dark purple. The fronds seldom appear before the end of May
or beginning of J u n e ; at first their position is nearly erect, hut
they soon begin to droop, and finally become quite pendulous :
they arrive at maturity in September, and continue perfectly
green and vigorous throughout the winter, and until the ensuing
May or even June : they are always fertile.
The form of the frond is triangular, the apex being acute and
attenuated ; it is pinnate : the pinnæ are triangular, acutely
pointed, pinnate and alternate ; the pinnulæ again are alternate
and triangular, and the lower ones pinnate or pinnatifid, with
their lobes notched; the fronds represented are of the natural size,
but are drawn from fronds which may be less than the average.
The lateral veins in the pinnulæ or lobes, as the case may he,
are irregularly alternate, and generally forked after leaving the
midvein, and one or both branches of this divided vein bears an
elongate linear mass of thecæ ; these masses are always situated
near the midvein, and at first are completely covered by a long,
narrow, white, scale-like indusium, which opens towards the
midvein, and as the thecæ swell and approach maturity, it is
raised, pushed from its site, turned aside, and finally entirely
disappears, and the under-surface of the frond becomes a continuous
mass of rich brown seed.
The superior length of the lower pinnæ, and the oblique angle
at which these, and indeed all the pinnæ, are attached to the
rachis, and, lastly, the more central situation in the pinnulæ
occupied by the thecæ, are characters by which this species may
he readily distinguished from the preceding.
I, «I
I