Reseda. Reseda luteola. Dyer's weed.
Reseda. Reseda Luteola L. Weld. Dyer's Weed. Herbe Jaune, Gaude, Fr. Wau, Gelbkraut, Harnkraut, Gr. (Fam. Resedaceae.)—An annual European plant, naturalized on roadsides and ballast from Massachusetts to Pennsylvania. The plant grows to a height of 6 dm., possesses alternate lanceolate leaves and small greenish-yellow flowers. It is inodorous, and has a bitter taste, which is very persistent. Volhard showed that allyl thiocyanate, C3H5.SCN (volatile oil of mustard), was present in the root, and Chevreui obtained from it by sublimation a peculiar yellow coloring matter, which he called luteolin. Hlasiwetz and Pfaundler (1805) assign to it the formula C15H10O62H2O and find it to be tetrahydroxyflavone. This forms yellow crystals of silky luster, insoluble in water, soluble in alcohol. It dissolves in alkalies with deep yellow color. It is used especially in silk dyeing. A. G. Perkin (J. Chem. S., 1896) investigated the salts of luteolin, and called attention to the similarity of its properties to those of fisetin. In medicine it has been employed as a diaphoretic and diuretic, but it is now used only for dyeing purposes.