Primrose is the common name for the flower Primula vulgaris, and of several other (but not all) species in the genus Primula. In America, Primula vulgaris is known as the "English" Primrose.
Members of the genus Primula which are not commonly called primroses include cowslips, oxslips , auricula .
The Evening primrose (Oenothera) is a completely different, unrelated plant belonging to the family Onagraceae.
Cyclamens are also sometimes referred to as primroses.