Cayaponia is among the largest genera in the gourd family, Cucurbitaceae, with 74 species. The plants are referred to as melonleaf. They are common from the southern United States to South America. Some species are also found in western Africa, Madagascar, and Fernando de Noronha, which is about 354 km (220 mi) off the coast of Brazil.

Most species are found in rainforests and have white or yellow-green flowers. The ancestral mode of pollination in Cayaponia was inferred as pollinated by bats, but at least two shifts to bee pollination are inferred among some of its species. This is apparently the first clade to shift from bat to bee pollination vice bee to bat pollination. A 2011 phylogenetioc study placed the genus Selysia under this genus.

Brazilian botanist António Luiz Patricio da Silva Manso named this genus after the indigenous Cayapo people of Brazil.

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