Related entry: Aspidium

The whole plants of Pteris atropurpurea, Linné, and other species of Pteris.
Nat. Ord.—Filices.
COMMON NAME: (1) Rockbrake; (2) Common brake.

Botanical Source.—Rockbrake is an indigenous perennial fern, with a frond 6 to 10 inches in height, twice as long as wide, of a grayish hue, pinnate, the two lower divisions consisting of 1 to 3 pairs of leaflets, with a large terminal segment. The stipe and rachis are dark-purple, shining, with dense, paleaceous hairs at base. The lower leaflets are ternate or pinnate, lanceolate, obtuse, distinct, obliquely truncate or subcordate at the base, with margins conspicuously revolute. The involucre is rather broad, and formed of the inflected margin of the frond, opening inwardly. The sari are in a broad, continuous line along the margin of the frond. The several varieties of this species possess similar properties, as the Pteris venosa, with the stipe angled, and leaflets veined beneath; P. punctata, with the stipe terete, and the leaflets punctate beneath (W.—G.).

The Pteris aquilina, Linné, or Common brake, likewise possesses analogous virtues. It is a fern 2 to 5 feet in height, upon a smooth, dark-purple, erect stipe. The frond is pinnate, 3-parted, broad-triangular in outline; the branches bipinnate; the leaflets linear-lanceolate; the lower ones pinnatifid, upper ones entire; the segments oblong and obtuse. The sori are covered by the folding back of the margins of the segments (W.).

History, Description, and Chemical Composition.—Rockbrake is common to the United States, usually rowing on limestone rocks; the common brake is found in great abundance in woods, pastures, waste grounds, and stony hills. The whole plant is used in medicine, and imparts its virtues to water. As found in commerce, the dried root consists of a long cylindrical caudex, of a dark-brown color externally, and a light brownish-red internally, of an astringent, leathery taste, and around which are closely arranged, overlapping each other like the shingles of a roof, the remains of the leaf-stalks or stipes, which are 1 or 2 inches in length, from 2 to 4 lines thick, somewhat curved and directed upward, angular, dark-brown, furrowed longitudinally, and from between which emerge numerous small, radical fibers. The dried leaves are of a light-grayish or greenish-yellow color, of an odor resembling that of sole-leather, and a leathery, astringent, not disagreeable taste. As sold, it is usually in broken fragments. According to Wackenroder, the root of the common brake contains a bitter substance, fatty oil, mucilage, starch (33.5 per cent), tannin, etc. It also contains volatile oil and filicin, a derivative of the phenol phloroglucin (C6H3[OH]3).

Action, Medical Uses, and Dosage.—Rockbrake is astringent and anthelmintic. A decoction of it, taken moderately, has proved efficient in diarrhoea, dysentery, night-sweats, and hemorrhages; and, used as a local application, it is beneficial in obstinate and ill-conditioned ulcers, ulcerations of the mouth and fauces, and as a vaginal injection in leucorrhoea. A strong decoction is in repute as a remedy for worms. A powerful astringent infusion may be made by adding 4 drachms of the plant to 1 pint of boiling water, and which has been used in diarrhoea and dysentery, in ½ fluid ounce doses, repeated every 2 or 3 hours, with success. A tincture of the fresh entire plant (℥viii to alcohol, 76 per cent, Oj) is suggested in from 1 to 10-drop doses (Scudder). Pteris aquilina is sometimes called Female fern, and has been used to expel tapeworm.

A plant called Winter fern, or Brake, is much employed in amenorrhoea and in suppression of the lochia; it is used in infusion and taken freely. By some it is supposed to be the Pteris atropurpurea, but of this I am not positive, not having been able to obtain a perfect specimen of the plant for examination. Both the roots and tops are used, and are worthy the attention of the practitioner in the above-named derangements (J. King).

King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.