à/J [ 1950 ]
A S P L E N I U M Adiantum-nifOfrum.
Black Maidenhair Spleenwort.
CRYPTOGAMIE Filices.
Gen. Char. Fructif. in scattered lines. Involucrum
originating laterally from a vein, and bursting inwardly.
' Spec. Char. Frond somewhat dçltoid, alternately
thrice pinnated ; leaflets lanceolate, sharpish, deeply
serrated.
Syn. Asplénium Adiantum-nigrum. Linn. Sp. PL 1541.
Sm. FI. Brit. 1131. Hurls. 454. With. 770.
Hull. 242. Relh. 409. Siblh. 269. Abbot. 225.
Bolt. Fil. 30. t. 17.
Adiantum nigrum officinarum. Raii Syn. 126. n. 10.
also 127. n. 12, 13.
F r e q u e n t in dry shady hedge bottoms, about the roots
of old trees, on ruined buildings and among rocks, bearing
seed in the' summer and autumn.
Root perennial, black and tufted. Frond's numerous, upright,
a foot or thereabouts in height, firm, oblong, but assuming
a deltoid or triangular figure from the elongation of
their first pair of ramifications. They are throughout alternately
tripinnate; the leaflets rather acutely and deeply serrated
or cut, except at their base, which is entire and wedge-
shaped. The colour of the frond is a darkish shining green ;
that of the stalk deep purple, and polished. The covers of
the fructification are very conspicuous for their whiteness and
abundance. Capsules red-brown.
The variety /3 of FI. Brit, which is No. 13 of Ray’s Synopsis,
was found by Sherard in a dark cave on the mountains of
Mourne, Ireland, and is preserved in his herbarium at Oxford,
where, by the kind permission of Professor Williams, we
have examined it. Nothing can be more delicate and elegant
than the specimen. We think with Dillenius it most probably
belongs to this species, and it seems analogous to the
variety of Polypodium vulgare, called the cambricum, being
like that finely cut and destitute of fructification.