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 persica × Prunus americana tree is included in the Purdue University book "Fruit Breeding", Volume 1. The hybrid at Broadus, Montana has never fruited as the flowerbuds have all winterkilled. The hybrid has bloomed in Pennsylvania and the blooms are sterile. As of 2013, the hybrid near Broadus is still alive. Prunus persica × Prunus americana Prunus persica" × "Prunus americana is the hybrid between the peach "Prunus persica" (often a nectarine) and the wild American plum "Prunus americana". Hybrids were obtained in the 1940s at the University of Minnesota, and have been used in subsequent breeding, such as in the parentage of a