Which plant has the highest number of species in  Hottonia or Spiraea
Hottonia Hottonia is a genus of aquatic flowering plants in the family Primulaceae. It comprises two species:
Stylochaeton Stylochaeton is a genus of flowering plants in the Araceae family that is endemic to Africa. "Stylochaeton" are rhizomatous with hastate leaves. Flowering in this genus is said to be quite uncommon.