Question: Which genus has more species, Petunia or Kigelia? 

Context paragraphs:
Kigelia: Kigelia is a genus of flowering plants in the family Bignoniaceae.  The genus comprises only one species, Kigelia africana, which occurs throughout tropical Africa from Eritrea and Chad south to northern South Africa, and west to Senegal and Namibia.  The Kigelia grows a fruit that grows up to 2 feet long, weighs about 15 lbs, and looks like sausage.

Petuvirus: Petuvirus is a genus of viruses, in the family Caulimoviridae.  Plants serve as natural hosts.  There is currently only one species in this genus: the type species Petunia vein clearing virus.  Diseases associated with this genus include: plants: chlorotic vein clearing, leaf malformation.

Petunia: Petunia is genus of 35 species of flowering plants of South American origin, closely related to tobacco, cape gooseberries, tomatoes, deadly nightshades, potatoes and chili peppers in the same family, Solanaceae.  The popular flower of the same name derived its epithet from the French, which took the word "petun", meaning "tobacco," from a Tupi–Guarani language.  An annual, most of the varieties seen in gardens are hybrids ("P." × "atkinsiana", also known as "P." × "hybrida").

Petunia exserta: Petunia exserta is a rare member of the genus "Petunia", endemic to the Serras de Sudeste in southern Brazil.  First described in 1987, only fourteen plants were found in the wild during an expedition in 2007.  In the wild, the plant is found growing only in shaded cracks on sandstone towers.  It is the only "Petunia" species that is naturally pollinated by hummingbirds, and the only red flowered "Petunia" species.

Supporting paragraphs: Petunia Kigelia
Answer: Petunia