Classif. Nat. Order of Geranides. Decandria pentagynia. L.
Genus OXALIS. Calix five parted, persistent. Corolla of five petals, slightly connected at the base. Ten stamina, monadelphous at the base, five alternate shorter. Five styles and stigmas, capsule pentagone, dehiscent at the angles, five locular cells, two or many seeded; seeds with an elastic axilla.
Sp. Oxalis acetosella. Stemless, creeping, petioles and scapes long, filiform and pilose, leaves with three folioles, broad obcordate pilose, ciliate, scapes uniflore, erect.
Description. Roots perennial, creeping, white, juicy, with some little fleshy knobs, leaves nearly radical, on long slender filiform hairy petioles, three folioles, subsessile, more or less pilose, ciliated, obcordate, broad, glaucous beneath: scapes similar and equal to the petioles, with two small adpressed bracts on the middle, one terminal flower, white, with purple veins. The five longest stamina equal to the styles.
History. This plant is scattered in both continents, in woods, groves, and hedges; but in America seems confined to the boreal and mountain regions. It blossoms in summer. It has many varieties—1. Minor, (figured here) with small leaves, not very broad nor pilose, small erect flowers, with obtuse petals. In Canada, New York, New England. 2. Montana, with large, very broad, and short leaves, nearly glabrous and reticulated, but ciliated, flowers large, erect, with retuse petals, and a yellow spot at the base of each. On the Catskill and Alleghany mountains. These appear almost different species, but they are connected by the European varieties, such as, 3. Cespitosa. Leaves cespitose, flowers bluish-white. 4. Nutans. Leaves broad, pilose, flowers nodding, smaller, &c. Many other species are found in North America, which have mostly yellow flowers on a stem, except the O. violacea, which is stemless, and has purple blossoms. The O. sanguinolaria of Louisiana, has yellow blossoms, with bloody spots inside. They are all called Wood-sorrel; are small scentless plants, with a sharp acid tastes, and have all similar properties.
Properties. Acid, refrigerant, attenuant, antiputrid and diuretic. Useful in decoction as a cooling drink in inflammatory disorders, fevers, piles, putrid diseases, &c. Boiled in milk they form a good acid whey, very cooling. They may also be eaten in sallad: they are peculiarly useful in diseases of the kidneys, bladder, and urethra, when they are inflamed and painful, acting as cooling diuretics. They are often substituted to common sorrel and sheep sorrel; but they must not be eaten to excess, because they contain a violent poison, the oxalic acid; in small quantity, however, since 100 pounds of leaves give only 30 pounds of juice, and this only 10 ounces of the super oxalate of potash, which is sold and used by the wrong name of Salt of Lemons, for making a bad and dangerous imitation of lemonade, and for taking off ink stains from linen, cloth and paper. A good conserve and syrup of oxalis leaves were made, which are pleasant medical preparations,: they are now, however, superseded by currant jelly and other preparations of acid fruits.
Medical Flora, or Manual of the Medical Botany of the United States of North America, Vol. 2, 1830, was written by C. S. Rafinesque.