Persian berries, also called buckthorn berries, are small berries from any shrub of the buckthorn family, such as Rhamnus infectorius, R. amygdalinus, R. oleodies, or R. alaternus. Buckthorn plants are native to the near East and have been cultivated in Europe since Roman times. A water-soluble dye was extracted from the berries for use in lake pigments. The unripe berries produce a yellow juice or sap that is used for making a yellow pigment called sap green. The ripe berries were used to make Dutch pink, a yellow lake. The principle colorant, rhamnetin, is extracted from the dried berries by boiling water. Some plants also contain other colorants such as kaempferol (R.cartharticus), quercetin, xanthorhamnin and emodin. Sap green lake is made with alum and can vary in colour from yellow to green. A fugitive yellow colour prepared on alum was widely used in house paints in England in the 18th century. Persian berries are listed among the additional pigments used for colouring stucco marble in the nineteenth century. Synonyms: French berries; buckthorn berries; dyer's buckthorn; Persian berry lake; yellow berries; sap green; Dutch pink; grain d' Avignon (Fr.); Avignon berries; Gelbbeere (Ger.) Spincervino (Ital.) Espino cerval (Sp.); Persische bessen (Dut.); rhamnetin Wittenburg (1999); Museum of Fine Arts, Boston (2000). [J. Cassar, R. de Angelis]