POLYPODY; a genus of the order of filices, belonging to the cryptogamia class of plants. There are 65 species, of which the most remarkable is the filix mas, or common male fern. This grows in great plenty throughout Britain in woods and stony soils. The leaves are a cubit high, and grow in circular tufts. They are at first alternately pinnate, the pinnae increasing in size from the base towards the middle, and afterwards gradually decreasing upwards to the summit of the leaf. These pinnae are again pinnatifid, or subdivided almost to the nerve into obtuse parallel lobes, crenated on the edges. The stalks are covered with brown silky scales. The fructifications are kidney-shaped, and covered with a permanent scaly shield or involucremum. The capsules are of a pale brown, surrounded with a saffron-coloured elastic ring.

This fern has nearly the same qualities, and is used for most of the same intentions as the pteris aquilina. They are both burnt together for the sake of their ashes, which are purchased by the soap and glaze-makers. In the island of Jura are exported annually 150l. worth of these ashes.

Gunner relates, in his Flor. Norveg., that the young curled leaves, at their first appearance out of the ground, are by some boiled and eaten like asparagus; and that the poorer Norwegians cut off those succulent laminae, like the nails of the finger at the crown of the root, which are the bases of the future stalks, and brew them into beer, adding thereto a third portion of malt, and in times of great scarcity mix the same in their bread. The same author adds, that this fern cut green and dried in the open air, affords not only an excellent litter for cattle, but, if infused in hot water, becomes no contemptible fodder to goats, sheep, and other cattle, which will readily eat, and sometimes grow fat upon it; a circumstance well worth the attention of the inhabitants of the Highlands and Hebrides, as great numbers of their cattle, in hard winters, frequently perish for want of food.

But the anthelmintic quality of the root of the male fern is that for which it is chiefly to be valued, and of which an account is given under the article Medicine, n° 493.