Dandelion (the English corruption of the French dent de lion, lion's tooth, so named from the tooth-like lobes of its leaves) is the popular name of Taraxacum officinale, a very common perennial weed in the northern hemisphere belonging to the sub-order Cichoraceae of the order Compositae. The black rhizome is roasted as a substitute for, or adulterant of, coffee, and the leaves, which form a rosette and are bitter when green, are, when blanched, an excellent salad. The peduncles of the numerous scapes are glabrous, hollow, and brittle. The involucre consists of two whorls of green bracts, the outer reflexed and the inner spreading; all the florets are alike ligulate and bisexual with golden-yellow corollas, forming a head 1-1/2 inches across. The common receptacle is flat and naked, but becomes rounded after flowering, so that the fruits, which are each surmounted by a stalked pilose pappus, form a white globe nearly 2 inches in diameter. The plant flowers from April to August, the heads only remaining expanded from about 5 a.m. to 9 p.m. The whole plant contains abundant milky latex, which coagulates on exposure, becoming a violet-brown. In contains caoutchouc and a diuretic principle, taraxacin.