Rhamnus Cathar'Tica, Buckthorn. The nearly ripe fruit (berries), official 1820-1840, Europe, N. Asia, naturalized in N. America. Small tree, 3-4.5 M. (10-15°) high, short branches, thorny; leaves 2.5-5 Cm. (1-2') long, 2.5 Cm. (10 wide; flowers greenish; fruit Sept., black berries, size of a pea, green juice, 3-4-seeded; taste bitter, acrid; contains emodin-autranol, gesterin, rhamno-cathartin (a glucoside of emodin) - emodin, rhamnonigrin, resin (containing emodin), rham-nose, glucose, fixed oil, quercetin and rhamnin (yellow coloring matter). Used as a cathartic. Dose, 3 ss-1 (2-4 Gm.); decoction, fluidextract (dil. alc), syrup, 20 p. c. (fldext.), expressed juice made into syrup. Fresh juice with alum or lime yields the pigment sap green. R. carolinia'na, Carolina (Southern) Buckthorn, New York to Texas. Shrub or small tree; leaves oblong, serrate; flowers short-peduncled; fruit purple, 3-seeded.