in botany; a genus of the order of filices, belonging to the cryptogamia clas of plants. The fructifications are in lines under the margin. There are 19 species; the most remarkable is the aquilina, or common female fern. The root of this is viscid, nauseous, and bitterish; and like all the rest of the fern tribe, has a salt, mucilaginous taste. It creeps under the ground in some rich soils to the depth of five or six feet, and is very difficult to be destroyed. Frequent mowing in pasture-grounds, plentiful dunging in arable lands, but, above all, pouring urine upon it, are the most approved methods of killing it. It has, however, many good qualities to counterbalance the few bad ones. Fern cut while green, and left to rot upon the ground, is a good improver of land; for its ashes, if burnt, will yield the double quantity of salt that most other vegetables will.—Fern is also an excellent manure for potatoes; for if buried beneath their roots, it never fails to produce a good crop.—Its astringency is so great, that it is used in many places abroad in dressing and preparing kid and chamois leather.—In several places in the north, the inhabitants mow it green, and burning it to ashes, make those ashes up into balls, with a little water, which they dry in the sun, and make use of them to wash their linen with instead of soap. In many of the Western Isles the people gain a very considerable profit from the sale of the ashes to soap and glas makers.—In Glen Elgin Invernessshire, and other places, the people thatch their houses with the stalks of this fern, and fatten them down with ropes made either of birch-bark or heath. Sometimes they use the whole plant for the same purpose, but that does not make so durable a covering.—Swine are fond of the roots, especially if boiled in their wash.—In some parts of Normandy we read that the poor have been reduced to the miserable necessity of mixing them with their bread. And in Siberia, and some other northern countries, the inhabitants brew them in their ale, mixing one-third of the roots to two-thirds of malt.—The ancients used the root of this fern, and the whole plant, in decoctions and diet-drinks, in chronic disorders of all kinds, arising from obstructions of the visera and the spleen. Some of the moderns have given it a high character in the same intentions, but it is rarely used in the present practice. The country people, however, still continue to retain some of its ancient uses; for they give the powder of it to destroy worms, and look upon a bed of the green plant as a sovereign cure for the rickets in children.