Asclepias syriaca. Common Silkweed.
Nat. Ord. — Asclepiadacere. Sex. Syst. — Pentandria Digynia.
Description. — Asclepias Syriaca, (the Asclepias Cornuti of Decaisne,) known as Milkweed in many parts of the country, has a large, stout, simple, somewhat branched stem, growing from two to five feet high. The leaves are opposite, oblong-lanceolate, petiolate, gradually acute, and tomentose beneath. The flowers are large, and sweet-scented, arranged on several umbels, which are axillary, subterminal, nodding, dense, globose, each of twenty or more flowers. Calyx segments lanceolate. Corolla pale or greenish-purple, reflexed, leaving the corona, which is of nearly the same hue, quite conspicuous. But few of the flowers prove fertile, producing oblong, pointed pods or follicles covered with sharp prickles, which contain a mass of long, silky fibers with seeds attached, and which fibers have been used for beds, pillows, and in the place of fur in manufacturing hats.
History. — Very common to the United Slates, growing in sandy fields, on roadsides, and on banks of streams. It bears whitish-purple flowers in July and August. The plant also gives out a milky juice when wounded. It contains water, wax-like fatty matter, caoutchouc, gum, sugar, with various salts. A crystalline resinous substance, allied to lactucone, has been obtained from the juice of the A. Syriaca, to which the name of Asclepione has been given. To obtain it, the juice must be coagulated by heat, then filtered, to separate the liquid portion, and then digested with ether, which dissolves the asclepione, and yields it by evaporation. To purify it, treat the residue repeatedly with anhydrous ether, which leaves another substance undissolved. Asclepione is white, crystalline, tasteless, inodorous, fusible, insoluble in water or alcohol, soluble in ether, oil of turpentine, or concentrated acetic acid ; potassa in a hot strong solution does not affect it.
Properties and Uses. — Anodyne, emmenagogue, diuretic and alterative. Useful in amenorrhea, dropsy, retention of urine, dyspepsia, asthma, cough, dyspnoea, also, in scrofulous and rheumatic disorders. Both the root and inspissated milky juice possess anodyne properties. Dose of the powder, ten to twenty grains ; of the decoction, two to four ounces ; of the tincture, ten to sixty minims.