A recently-published article (Moreira et al. 2015) has suggested that urucú (or annatto; Bixa orellana), a plant whose seeds produce a widely-used coloring agent, was probably domesticated in South America. Rondônia (western Brazil), the likely birthplace of cassava, is once again a strong candidate to have given the world yet another important agricultural item. For the historical linguist, a fascinating piece of information — not mentioned in the article — strongly corroborates the antiquity of the plant in the region: a name for 'urucú' can apparently be reconstructed for Proto-Tupí (cf. Rodrigues 2010), which is supposed to have been spoken in Rondônia about 5 thousand years ago.