Psoralea. Psoralea esculenta. Prairie turnip, Prairie potato.
Psoralea.—Of this genus (Fam. Leguminosae) various species are useful. The tubers of P. esculenta L. are employed by the Indians of the Northwestern United States, and by the settlers, as articles of food, being the prairie turnip or prairie potato, the tipsinah and taahgu of the Indians. C. Richardson found in it nearly 70 per cent. of starch, and 5 per cent. of a new, rapidly crystallizing sugar, which has not been further investigated. P. glandulosa L., culen, yolochiahiti, of the Mexican Pharmacopoeia, yields a leaf which is used as a tonic or anthelmintic, and an emetic root. P. bituminosa L., of Europe, and P. physodes Dougl., of California, are popularly considered tonic and emmenagogue, the former being presented under the name of Herba Trifolii Bituminosi. P. pedunculata (Mill.) Vail. (P. melilotoides Michx.) (Congo root, Bob's root, Samson's snakeroot), of Virginia, has been recommended as an aromatic bitter tonic, especially useful in chronic diarrhea. The part employed is the root, from which MacNair obtained about 2 per cent. of a volatile oil, having the specific gravity 0.93, a pungent and bitter taste, and a neutral reaction; also a bitter principle, but not tannin. For further description, see A. J. P., July, 1889; also 14th and 16th editions of U. S. D. P. corylifolia L., of India, yields an oleoresin which is used in the treatment of leucoderma and other skin diseases. (P. J., Sept., 1881.) Mann and Griffiths obtained from the seeds of P. coryfolia 13.7 per cent. of a thick brownish oil and 37.2 per cent. of an alcoholic extract which yielded by purification 9.2 per cent. of a resinoid. (P. J., 1912, 260.)