Which plant’s genus has the most other species, Purshia or Bergerocactus?
Purshia: Purshia (bitterbrush or cliff-rose) is a small genus of 5-8 species of flowering plants in the family Rosaceae, native to western North America, where they grow in dry climates from southeast British Columbia in Canada south throughout the western United States to northern Mexico. Bergerocactus:  It is the sole member of the genus Bergerocactus, named after Alwin Berger.
Purshia