Plum, fruit tree of a genus of the rose family, which also contains the other trees that produce drupes (hard-stoned fruits): peach, cherry, almond, and apricot. About 12 plum species are cultivated throughout temperate regions for their fruit and as flowering ornamentals. The trees are rarely more than 10 m (33 ft) tall and are suited to both warm and cool climates.

The common plum, the most important species, has been cultivated since ancient times and probably originated near the Caspian Sea, although its history is complicated and may involve some hybridization. Fruits of cultivated varieties of this species range in colour from yellow or red to green, but purplish-blue is most common. Dried plums, or prunes, are made from the varieties that are richest in sugar and solids.

The Japanese plum probably originated in China. The fruit is more pointed at the apex than that of the common plum, and its varieties are yellow or light red but never purplish-blue. The trees that produce damson—a small, oval, sweet fruit used mostly in jams—belong to the same species as a wild European tree, the bullace. All three species are so similar to the common plum that they are sometimes classified as the same species.

Scientific classification: Plums belong to the genus Prunus of the family Rosaceae. The common plum is classified as Prunus domestica, the Japanese plum as Prunus salicina, and both the damson and the bullace as Prunus insititia.

Reviewed by: Department of Botany, Natural History Museum