Prunus spinosa the British Army, blackthorn sticks are carried by commissioned officers of the Royal Irish Regiment; this is a tradition also in Irish regiments in some Commonwealth countries. The leaves resemble tea leaves, and were used as an adulterant of tea. Shlomo Yitzhaki, a Talmudist and Tanakh commentator of the High Middle Ages, writes that the sap (or gum) of "P. spinosa" (which he refers to as the ) was used as an ingredient in the making of some inks used for manuscripts. The fruit stones have been found in Swiss lake dwellings. Evidence of the early use of sloes by
Prunus americana Prunus americana Prunus americana, commonly called the American plum, wild plum, or Marshall's large yellow sweet plum, is a species of "Prunus" native to North America from Saskatchewan and Idaho south to New Mexico and east to Québec, Maine and Florida. "Prunus americana" has often been planted outside its native range and sometimes escapes cultivation. It is commonly confused with the Canada plum ("Prunus nigra"), although the fruit is smaller and rounder and bright red as opposed to yellow. Many cultivated varieties have been derived from this species. It forms an excellent stock upon which to graft the domestic plum.