Which genus of plant had more species identified with it in the past, Carissa or Aruncus?
Aruncus:  Botanical opinion of the number of species differs, with from one to four species accepted. Carissa: Carissa is a genus of shrubs or small trees native to tropical and subtropical regions of Africa, Australia and Asia. Carissa:  Until recently about 100 species were listed, but most of them have been relegated to the status of synonyms or assigned to other genera, such as "Acokanthera".
Carissa