The scientific name of the 梅 is Prunus mume.
Plums cultivated in the US are usually hybrids of Prunus salicina with Prunus simonii and Prunus cerasifera. Just to confuse everyone, these are often called “Japanese plums,” although they actually originate in China.
European plums and dried plums (prunes) are usually Prunus domestica.
Apricots in the US and Europe are usually Prunus armeniaca. Peaches are Prunus persica, though they were first domesticated in China.
As the names suggest, all of these are pretty closely related and look pretty similar to someone who isn’t an orchard keeper or other expert. Differences have to do with color, taste, texture, how easy the seed is to remove, shelf life, frost tolerance, etc.