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
Tetradymia spinosa flower heads which are each enveloped in four to six woolly phyllaries. Each head contains up to 8 tubular yellow flowers up to a centimeter long. The fruit is a densely hairy achene which may be nearly 2 centimeters long, including its pappus of long bristles. Tetradymia spinosa Tetradymia spinosa is a species of flowering plant in the aster family known by the common name shortspine horsebrush. It is native to the western United States, especially the basins and plateaus west of the Rocky Mountains. It grows in sagebrush, woodlands, and scrub habitat, often among shadscale in alkaline areas such