Fig. 129. Helianthemum canadense. The plant Helianthemum canadense, Michaux (Cistus canadensis, Linné).
Nat. Ord.—Cistaceae.
COMMON NAMES: Frostweed, Frostwort, Frostplant, Rock-rose.

Botanical Source.—This plant is a perennial herb, with a simple, ascending downy stem, about 1 foot high, at length shrubby at base. The leaves are alternate, from 8 to 12 lines long, about one-fourth as wide, oblong, acute, lanceolate, erect, entire, subsessile, tomentose beneath, and without stipules. The flowers are large and bright yellow, few, in terminal corymbs; apetalous ones smaller, lateral, solitary or racemose, clustered in the axils of the leaves, and nearly sessile. The corolla, of the petaliferous flowers, are 1 inch wide, with 5 petals, crumpled in the bud, and fugacious. Calyx of the large flowers hairy-pubescent, and 5; of the small flowers, hoary. Stamens of the large flowers numerous and declinate; of the small flowers, few. Style short or none. Stigmas 3-lobed, scarcely distinct; capsule smooth, shining, triangular, 3-valved, 1-celled, opening at top, about 3 lines long; of the apetalous flowers not larger than a pin's head; the seeds are angular, few, and brown. The yellow flowers open in sunshine, and cast their petals by the next day (G. W.).

History.—This plant grows throughout the United States in dry, sandy soils, and flowers from May to July. The large flowers make their appearance first and later in the season the smaller flowers are produced on the same or other plants. The whole plant is medicinal. The leaves and stems of the plant are covered with a white down, and Prof. Eaton, in his work on botany, says: "In November and December of 1816, I saw hundreds of these plants sending out broad, thin, curved ice crystals, about an inch in breadth, from near the roots. These were melted away by day, and renewed every morning for more than 25 days in succession." These spicules of ice are sent out from fissures in the bark of the plant near its base. The plant has a bitterish, astringent, slightly aromatic taste, and yields its properties to hot water.

Chemical Composition.—Analyzed in 1888 by W. Crutcher (Amer. Jour. Pharm., 1888, p. 390), frostweed was found to contain tannin (10.8 per cent), wax, fatty and volatile oils. A white crystalline principle, thought to be a glucosid, was obtained in fine needles by treating an alcoholic extract with water and shaking out with benzol. These crystals were not further examined.

Action, Medical Uses, and Dosage.—This plant has long been used in practice as a valuable remedy for scrofula, in which disease it has been reported to have effected some astonishing cures. It is used in the form of decoction, syrup, or fluid extract; if taken in too large doses it will sometimes vomit. It is tonic and astringent, as well as antiscrofulous. In secondary syphilis, either alone, or in combination with corydalis and stillingia, it was formerly regarded as a most valuable remedy. In the form of infusion, it has also been found very serviceable in chronic diarrhoea and dysentery, especially when occurring among persons disposed to scrofula, also as a remedy in several forms of cutaneous disease; also as a gargle in scarlatina and aphthous ulcerations, and as a wash in scrofulous ophthalmia, prurigo, and other cutaneous diseases. Externally, a poultice of the leaves is applied to scrofulous tumors and ulcers. The fluid extract is the best form for internal use; dose, 1 or 2 fluid drachms, 3 or 4 times a day. (For a list of physiological phenomena produced by this plant, in small and large doses, consult Millspaugh's Amer. Med. Plants, Vol. I, p. 28.)

Related Species and Drugs.Helianthemum corymbosum, or Frostweed, with an erect, branching, canescent stem; lance-oblong, alternate leaves, canescently tomentose beneath; flowers in crowded, fastigiate cymes; primary ones elongated, filiform pedicels, and with petals twice longer than the calyx; sepals villous-canescent, outer ones linear, obtuse; inner ones ovate, acute; is found growing in pine-barrens and sterile sands, in the southern and middle states. It possesses properties analogous to the preceding, and may be indiscriminately employed with it. F. J. Kruell, in 1874 (Amer. Jour. Pharm.), found it to contain resin, chlorophyll, gum, extractive, glucose, salts, and a large amount of tannin.

Helianthemum vulgare, Gaertner (Cistus Helianthemum, Linné). Europe. It has properties similar to the rock-rose.

LABDANUM, Resina ladanum.—This resinous exudate is derived from several species of Cistus, of the Nat. Ord.—Cistaceae, especially the Cistus creticus, Linné; Cistus ladaniferus, Linné; and Cistus cyprius, Lamarck. These are handsome evergreen shrubs, natives of the Levant and Grecian Archipelago. The resin is collected from the branches by means of a leather instrument somewhat like a rake—called labdanisterion—the implement being drawn over the branches and leaves, and the product scraped off the leather, to which it adheres. It is then kneaded or mixed together with sand or other solid material. Two grades of labdanum are met in commerce. The first form, cake labdanum, occurs as dark-brown or blackish masses, becoming soft and sticky by the warmth of the hands. When freshly broken it has a grayish aspect, soon changing to a darker hue. The second form, common labdanum, comes in cylindrical sticks, or spiral pieces, which are hard, brittle, light, porous, and of a gray-black color. Unlike the purer grade, it does not soften by the heat of the hand. Both varieties are bitter, and have a balsamic, pleasant odor. The second grade is usually much adulterated or wholly artificial. Pure labdanum is fusible, and burns with a vivid flame, is nearly completely dissolved by alcohol, but insoluble in water. The poorer grades are said to be gathered from the hair of goats and wool of sheep, which are allowed to browse on the plants. Cake labdanum, according to Guibourt (Hist. d. Drogues, 1875, Vol. III, p. 675), contains of resin and a small amount of volatile oil, 86 per cent; wax, 7 per cent; extractive, 1 per cent; hair, sand, and other insoluble matter, 6 per cent. Roll labdanum yielded to Pelletier, sand, 72 per cent; and resin, but 20 per cent. Labdanum was formerly regarded diuretic and expectorant, and was employed in bronchitis, leucorrhoea, catarrh, dysentery, etc. It is now used only in plasters, and is nearly obsolete as a medicine. Owing to its agreeable aroma when burned, it was employed by the ancients for fumigating purposes.

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