Plant Guide > Ferns > Common Prickly Shield Fern

Common Prickly Shield Fern


COMMON PRICKLY SHIELD FERN OR WILDENOW'S FERN

ASPIDIUM ACULEATUM

Synonyms:
Polystichum aculeatum
Polypodium

The Common Prickly Shield Fern is almost evergreen in a sheltered situation. It is a stout plant, having tufted fronds, rising from a short thick stem or crown from one to two feet high. Their form is lanceolate, twice-pinnate; the texture harsh and rigid; the upper surface dark green and shining; and the stalk or stipes, below the leafy part, from one to six inches long, very shaggy, with brown scarious scales.

The veins are alternately branched, and do not join together, but extend free to the margin. There is nothing remarkable in the fructification, which is generally abundant, beyond the regularity of arrangement in the sori, which lie in lines on each side of the mid-rib of the upper leaflets. The root is large and woody.

The European range of this fern extends to every country excepting Spain, where it has never yet been found. It is very commonly distributed throughout the United Kingdom, and is abundant on hedgerows, and in shady places in England. It seems to delight in cultivated districts, and is seldom found on open heaths or downs. This fern is easily managed in cultivation and bears exposure pretty well. It requires good drainage, and a fair allowance of sand and peat, and thus treated it forms a satisfactory member of the fernery.

The young fronds make their appearance in April, and attain their full expansion in July, while in August they are loaded with dark masses of fructification. They retain their green colour throughout the year, and the old fronds of one year may be seen contrasting with the delicate green of the young ones as they develop.

Varieties:

ASPIDIUM ACULEATUM LOBATUM chiefly differs in the narrow outline of the frond, which is simply pinnate. The pinnules are more decidedly decurrent. It is also of a more rigid texture; the pinnae lobed or pinnatifid.

The variety ASPIDIUM ACULEATUM ANGULARE is recognized by Moore and some other authors as a distinct species. It is a rather larger, more luxuriant, and less stiff variety; more divided than Aspidium aculeatum. The fronds lax, drooping, and lanceolate, with more distinct segments ; the lower pinnae evidently stalked.

The whole plant has a very vigorous appearance, and retains its green colour even in winter. The stalk is covered with a mass of scales of a rust-red colour, which are distinctly observable even in the young plant. Mr. Newman mentions a property as belonging to this fern, which, though common to many exotic species, is not found in any other British fern that of producing new plants from "bulbilli, which originate from the main or partial rachides at the axillae of the pinnules."

This condition of the plant was fully described by Professor Kinahan, in a paper read before the Dublin Natural History Society, in June 1852. If these bulbilli be taken off the parent pinnules and planted in a good light soil, they will grow with great rapidity, and form strong plants.