Ambrosia trifida. Tall Ambrosia.

Nat. Ord. — Asteraceae. Sex. Syst. — Monoecia Pentandria.

The Leaves.

Description. — Ambrosia Trifida is variously known by the names Horseweed, Bitter-weed, Great Rag-weed, Horse-cane, Rich-weed, etc. It is a rough, hairy, herbaceous, annual plant, with an erect, branching, furrowed stem, from five to ten feet in hight. The leaves are opposite, from four to seven inches broad, scabrous and hairy, with three large, deep lobes which are oval, lanceolate, acuminate and closely serrated ; the lower leaves are often five-lobed. Petioles narrowly-winged, ciliate ; racemes often paniculate. Flowers mean and obscure, in long leafless spikes, axillary and terminal. Fruit (fertile involucre) turbinate-obovoid, with a short conical pointed apex, six-ribbed, the ribs terminating in as many cristate tubercles.

History. — This plant grows in low grounds and along streams, from Canada to Georgia, and west to Louisiana and Arkansas, bearing greenish-yellow flowers in August. It is much in use among farmers, for the "slabbers" in horses, effecting a cure in a few hours. It has a spicy, pleasant, aromatic taste, slightly resembling ginger, and imparts its properties to water.

Properties and Uses. — This plant is slightly stimulant, astringent, and antiseptic. Useful in decoction as an injection in leucorrhea, prolapsus uteri, chronic gonorrhea, and gleet; also valuable as a collyrium, in ophthalmia, and as a wash or gargle — with its internal use also — in the sore mouth of nurses. It will be found an excellent application to mercurial, and all other ulcers of a fetid or gangrenous character. As a remedy for mercurial salivation, used every half hour as a wash, it is said to be prompt and efficacious. Internally, the decoction is useful in fevers, attended with a disposition to putrescency, diarrhea, and dysentery. Dose of the decoction from one to two ounces. Two preparations are said to have been obtained from this plant, called Ambrosine and Elatine. The former, it is stated, is found associated with elatine, and forms beautiful and brilliant, pearl-like, prismatic crystals with sulphuric acid; it is tasteless and inodorous, and can be retained on the most sensitive stomach. It is recommended as a tonic, diuretic, and alterative in dropsical affections with great loss of vitality ; in nephritis and albuminuria ; likewise in diabetes, consumption, scrofula, etc. Dose, one to three grains, three to six times a day. If this agent is as effectual as its manufacturers state, it will become one of the most valuable in the Materia Medica. — Elatine is obtained in the form of a white, flocculent precipitate. Properties and dose similar to ambrosine. We have not been able to learn the mode of preparing these articles.

The Ambrosia Artemisiaefolia (A. Elatior), Roman Wormwood, or Rag-weed, has a slender stem, rising from one to three feet high, much branched, and pubescent when young ; the leaves are opposite, and the upper alternate, twice pinnatifid, smoothish above, paler or hoary beneath ; barren flowers small, green, in terminal racemes, or spikes loosely panicled; the fertile ones sessile about the axils of the upper leaves ; fruit obovoid, or globular, pointed, armed with about six short acute teeth or spines. It is sometimes called Hog-weed. It is very common in all our fields, and would probably prove fully as efficacious, if not more so than the A. Trifida. It is highly recommended as a fomentation in recent inflammation from wounds or injuries of any kind. Made into a salve by bruising the green leaves, and simmering them in spirits and cream, it is very useful in hemorrhoidal tumors, and some forms of ulcer.

The American Eclectic Dispensatory, 1854, was written by John King, M. D.