Plum pox show no symptoms on leaves or fruit. Not all infection in "Prunus" are characterized by a ring symptom on leaves. Several cultivars show yellowing line patterns and blotches, or necrotic ring symptoms on expanded leaves. Leaf distortion has also been observed. Infected fruit can develop yellow rings or blotches, or brown rings, and some plum and apricot fruit can be severely deformed and bumpy. The seed of many infected apricots and some plums show rings. Many non-"Prunus" species, in at least nine plant families, have been infected artificially with one or more strains of the plum pox virus, and in
Plum or prunes, although, in many countries, prunes are a distinct type of dried plum having a wrinkled appearance. Plums may have been one of the first fruits domesticated by humans. Three of the most abundant cultivars are not found in the wild, only around human settlements: "Prunus domestica" has been traced to East European and Caucasian mountains, while "Prunus salicina" and "Prunus simonii" originated in Asia. Plum remains have been found in Neolithic age archaeological sites along with olives, grapes and figs. The name plum derived from Old English plume or "plum, plum tree," which extended from Germanic language or