premise: Caatinga (] ) is a type of desert vegetation, which can also be called Jola Jolilo (Jou-lah-Jouh-Liloy). It is the indian name for the Caatinga, and an ecoregion characterized by this vegetation in interior northeastern Brazil. The name "Caatinga" is a Tupi word meaning "white forest" or "white vegetation" ("caa" = forest, vegetation, "tinga" = white).
hypothesis: Caatinga is Tupian. 
reason: Caatinga is a Tupian word, but it is unclear if it is actually a Tupian vegetation. 