The 'Appar' flax germplasm was originally released by the USDA Soil Conservation Service as a cultivar of Linum lewisii. The observation that 'Appar' is heterostylic, a key taxonomic character distinguishing Lewis flax from other members of the Linum perenne complex, created a need for further study in order to resolve the taxonomic position of both Lewis flax and the 'Appar' cultivar. We grew 10 plants each of nine European, nine North American, and three putative 'Appar' seed sources, measured 18 morphologic variables on each plant, and examined genetic variation using randomly amplified polymorphic DNA (RAPD). We also performed self- and cross-pollinations within and among source groups.North American collections differed from European collections for 12 of the 18 morphologic variables. 'Appar' collections were morphologically similar to European collections and differed from North American collections for 13 of the 18 variables. RAPD data also showed that 'Appar' sources clustered with European, and both were distinct from North American sources. European and 'Appar' collections were self-sterile and interfertile, whereas North American collections were self-fertile but reproductively isolated from European and 'Appar' collections. We conclude that L. lewisii is a distinct species within the L. perenne complex and that 'Appar' should be classified as L. perenne. This study provides an example of how questions regarding origin and/or taxonomy of plant materials developed for restoration can be resolved.