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 xueluoensis pseudocerasus". Prunus xueluoensis Prunus xueluoensis is a species of "Prunus" found in Hubei and Jiangxi provinces of China. It is a shrubby tree 0.5 to 3m tall, preferring to grow at 1100 to 1500m above sea level. It is only known from three mountains; Xueluozhai, Lushan and Jinggangshan. It is morphologically similar to "Prunus tomentosa" and "Prunus tianshanica". It differs from them by a number of features including having two to four flowers per inflorescence, many more stamens per flower, a glabrous pistil and a black fruit. Genetically, "P. xueluoensis" is more closely related to "P. polytricha", "P. jingningensis", and