Antigonon is a genus of flowering plants in the buckwheat family, Polygonaceae.
 It contains three species native to the Americas.
Fontanesia is a genus of flowering plants in the family Oleaceae, usually treated as comprising a single species Fontanesia phillyreoides, though some authors split this into two species (see below).
 It is native to southern Europe (Sicily), southwestern Asia (Lebanon, Syria, Turkey) and eastern Asia (China), with two well-separated populations.

Question: Which genus has more species, Fontanesia or Antigonon?
Answer: Antigonon