Black Spleenwort Fern
THE BLACK SPLEENWORTASPLENIUM ADIANTUM NIGRUM
The name of the Black Spleenwort Fern is derived from the Greek word Asplenon, a name given by old authors to a fern said to be a remedy in diseases of the spleen.
This species, often called Black Maiden Hair, grows from six inches to a foot in height. The fronds are triangular or broadly lanceolate, the dark shining purple or black stalk being often as long as the leafy part. They are of a thick firm texture, with numerous veins, and of a dark green colour.
They are bipinnate, or sometimes tripinnate, the pinnae gradually decreasing and less divided towards the point of the frond. The sori are at first distinct, placed near the mid-rib; but as the plant becomes older, they are generally confluent in a mass, often covering the whole undersurface of the pinnule. It is one of the latest of our ferns in unfolding its fronds, which are not often open until the middle of June.
It is a conspicuous ornament of the situations where it occurs; chiefly on old walls, or hanging in graceful prays over rocks, or on the hedgebank of the dry but shady lane. The fronds grow erect or stooping, according to the position of the plant; they have generally a triangular outline. They are not crisp, like the fronds of most of our ferns, but have a leathery sort of texture, and are much veined. It is found only very sparingly in Ireland. This fern does not thrive well in the closed case, but does best on rock-work in the open air, in a shady situation.
When this fern assumes a much more blunt form, it constitutes the variety called by botanists Asplenium Adiantum nigrum obtusum; while sometimes it acquires a tapering slender shape, and is then called Asplenium Adiantum nigrum acutum; both these forms are rare in this country-on the Continent they are well known, and are considered so permanent as to be ranked as species.
Obtusum is found in dry, exposed places - acutum in sheltered, shady spots.