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 darvasica × "P. cerasifera"). Prunus darvasica Prunus darvasica, the Darvaz plum, is rare plant endemic to Tajikistan. It is found in the Tajik portion of the Pamir Mountains, the Darvoz Range. There, the plants grow as shrubs 1.5-2.5m tall. The fruit are small (2cm) but otherwise typical plums, nearly black, with a blue waxy coat. The pit is brown. The fruit is edible and can be made into jam or compote. It is suspected that "P. darvasica" is of hybrid origin, as it is a tetraploid with 48 (or 32, depending on the source) chromosomes, possibly the result of "P. domestica"