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 rivularis Prunus rivularis Prunus rivularis, known variously by the common names creek plum, hog plum, or wild-goose plum is a thicket forming shrub. It prefers calcareous clay soil or limestone-based woodland soils. This deciduous plant belongs to the rose family, Rosaceae, and is found mainly in the central United States. It is a shrub consisting of slender stems with umbel clusters of white blossoms. The fruit is a drupe that resembles a large berry; though it has a bitter taste, it serves as a source of food for birds and other wildlife. ""Prunus"" is Latin for plum, whereas ""rivularis"" means being