[Wikipedia] Description, Range, Variety Information: It is a low, stemless perennial that produces white flowers in the spring.[5] It can be distinguished from the similar-looking Viola lanceolata and Viola blanda by its leaves that are ovate, with rounded to truncate bases, and are 1.5-2 times as long as wide.[4]
While typical Viola primulifolia occurs in a large area of the east, a variety of this species is sometimes credited to occur in a small area of western California and Oregon, under the name of V. primulifolia var. occidentalis.[6] These populations, which are considered rare and highly localized, have alternatively been referred to as Viola lanceolata ssp. occidentalis (link added by Mary Ann Machi)