The Encyclopedia Americana (1920)/Sloe
SLOE, or BLACKTHORN, a European shrub (Prunus spinosa), from two to 15 feet high, much branched and very spiny. The small, white, rosaceous flowers appear before the leaves, which are alternate, ovate with obtuse tips and finely serrate. The fruit is a globose drupe about as large as a cherry, almost black, with a bloom, and containing a stone slightly flattened and acute on one edge. Its variety, the bullace (P. insititia), has by some been called a species and is supposed to be one of the plants from which European plums originated. The pits have been found in Swiss lake-dwellings, and the fruits have been used for preserves, for making fictitious port and adulterating the genuine wine and for a black dye. The leaves were an adulterant of tea and the stem furnishes the knobby “blackthorn” stick of Irish fame.