BUCKTHORN, Rhammus, a genus of shrubs or small trees of the natural order rhamname (q.v.), distinguished by a bell-shaped 4 to 5-cleft calyx, which divides around the middle after flowering, the upper part falling away, and the base remaining and adhering to the fruit; which is globose, and sometimes succulent, sometimes rather dry or spongy, with 2 to 4 stones. The petals are sometimes wanting. Some of the species are ditecious, some hermaphrodite. They are numerous, and natives of most of the tropical and temperate regions of the world.—The COMMON BUCKTHORN (R. eatharticus) is a deciduous shrub or low tree, frequent in England and in other parts of Europe and the n. of Asia. The leaves are ovate, crenate, and bright green; the branches spiny; the flowers small, yellowish-green, and densely clustered; male and female flowers on sepa rate plants; the berries about the size of peas, globular, bluish-black, nauseous, and vio lently purgative. They were formerly much used in medicine, but now more rarely, and only in the form of a syrup prepared from their juice. • They supply the sap green (q.v.) or bladder green of painters. The bark affords a beautiful yellow dye. The B. is sometimes planted for hedges, but is of too straggling a habit.—The ALDER BUCK THORN, or BERRY-BEARECCI ALDER (R. frangula), is also a native of I3ritain, and is fre quent in woods and thickets throughout Europe. It is a shrub, rarely a small tree, with spineless branches, oval entire leaves, and small, whitish, axillary flowers, which are in general somewhat clustered. The bark of the twigs is gray, and has a very disgusting
smell and a nauseous bitter taste. It was formerly used in medicine, along with that of the last species, and has recently been recommended in many quarters as a remedy for intermittent fevers. It contains principally an acrid bitter extractive, a volatile oil con taining hydrocyanic acid, and a yellow coloring matter called rhamnin. The berries are small and black, and violently i purgative. It is objected to their use in medicine that much sickness and thirst attend it. The charcoal of the wood is light, and is used for the preparation of gunpowder. The bark, leaves, and berries are used for dyeing; the bark for dyeing yellow, and with preparations of iron, black; the unripe berries to dye wool green and yellow; the ripe berries to (lye it bluish-gray, blue, and green. The flowers are peculiarly grateful to bees.—Dvmes BUCKTHORN (1?. infeCtOriOUS), is a low shrub, abundant in the s. of Europe, whose unripe fruit yields a brilliant yellow dye. The berries and inner bark of R. tinctorius, a native of Hungary, are also used in dye ing; • and the berries•of R. stcratilis; a procumbent.shrub, growing amongst rocks as far u. as Switzerland. The French berries. .1rignon berries, or yellow berries of dyers, are the fruit of R. iVectorios, B. B. a mygdatilur (or oleoides), and B. Clusii.—The SEA BUCKTHORN IS a shrub of n different genus and order. See SALLOW-THORN.