Professor Joan Edwards co-authored an article describing the Isle Royale Ragwort (Packera insulae-regalis), in Brittonia.
Packera insulae-regalis (Asteraceae, Senecioneae) is a new species that is only known from one population occurring near the summit of Mount Franklin on Isle Royale, Michigan, U.S.A. It resembles both P. paupercula and P. indecora but is hexaploid, whereas the former has diploid and tetraploid populations and the latter is octoploid around the western Great Lakes. Whereas most species of Packera are self-incompatible (as is P. paupercula) and a few are self-compatible (as is P. indecora), P. insulae-regalis is unique in the genus in being partially self-compatible, as far as is known. Its origin postglacially by hybridization between these two species is hypothesized.