Which genus of plants is within the Asteraceae family, Tithonia or Hymenocallis?
Tithonia Tithonia is a genus of flowering plants in the sunflower tribe within the Asteraceae family.
Helianthus nuttallii subsp. nuttallii H. nuttuallii subsp. nuttallii, also known by the common name Nuttall's sunflower is a subspecies of "Helianthus nuttallii" in the genus "Helianthus" in the family Asteraceae. It is considered by The Plant List to be a synonym for "H. nuttallii". However, The Jepson Manual argues that it is distinct from the species.