No. 76. Polygonum aviculare.

No. 76. Polygonum aviculare, P. persicaria. Names. Common Knotweed.
Fr. Renouee vulgaire.
Vulgar. Knotgrass, Birdweed.

Classif. Nat. Order of Polygonea. Octandria trigynia L.

Genus POLYGONUM. Perigone simple, unequal, colored and five parted. Stamens six to eight. One pistil, two or three styles and stigmas. One seed.

Sp. Polygonum aviculare. L. Annual, stem procumbent, branched, leaves lanceolate, scabrous on the margin; flowers axillary, eight stamens, three styles, seed triangular striated.

Description. A well known annual plant, very variable, procumbent or erect, diffuse, with many slender branches, leaves narrow lanceolate, sessile, acute at both ends, with nervose and membraneceous stipules. One to three axillary flowers on short peduncles, white or redish. Perigone persistent, with five unequal obtuse segments, &c. The varieties are: 1. Prostratum. 2. Erectum. 3. Diffusum. 4. Rubrum. 5. Parvifolium. 6. Linearifolium. 7. Gracile.

History. This genus includes the genera Fagopyrum or Buckwheat, Persicaria and Helxine, united by Linnaeus with little propriety, The Persicaria with two styles and a lenticular seed, form a very distinct subgenus at least. The Fagopyrum has an equal perigone, with a glandular nectarium. Polygonum means with many knots. This species is found every where in Europe and America, in fields, blossoming all the year round.

Properties. The whole plant is astringent, vulnerary, diuretic, subtonic, &c. although it has little smell and taste. It is useful in wounds, faintness, dropsies, prolapsus, hemorrhagy, and whenever mild astringents are required. In China, it is used as well as the P. chinense and P. barbatum, to die of a black and brown color. The P. convoloulus, distinguished by climbing stems and sagitate leaves, is called Chizahaw, by the Osages, and is used in dropsies, producing a profuse diuresis; large doses of a tea are taken; the leaves are smoked as a luxury and a fine tobacco. The P. bistorta, found in Long Island, according to Schoepf, is an officinal plant of Europe; the root is a strong astringent and styptic, equal to Geranium and Statice, useful in dysentery, leucorrhea, hemorrhagy of the stomach and uterus, &c.

The Polygonum persicaria, (or Persicaria maculata) is figured here No. 76, fig, 2. It has, as well as the other species of Persicaria (called Asmart, Smartweed, and Water-pepper) very strong properties, is an acrid diuretic, burning the tongue and even the skin, rubefacient, vermifuge, stimulant, incisive, &c. They have been much used in gravel, commonly infused in wine; are said to have cured odontalgy, sores of the ear, and aphthous sore mouth. Cutler relates, that the ashes make a soap which has been used as a nostrum to dissolve the stone in the bladder. Their tea is good in gravel, coughs, colds, and a good vermifuge. All cattle avoid them; they kill fish in ponds, and even snakes fear them. They die wool of a fine yellow, with alum; called Curage in Louisiana, and much esteemed. Schoepf says they cure the ulcers and sores of horses. The P. persicaria grows near waters all over the United States, and is easily known by its lanceolate leaves, with a black spot above, and oblong spikes of red flowers. The P. hydropiperoides, P. amphibium, P. pennsylvanicum, &c. are equally medical and equivalent to P. persicaria.

Medical Flora, or Manual of the Medical Botany of the United States of North America, Vol. 2, 1830, was written by C. S. Rafinesque.