Butia yatay, the jelly palm or yatay palm, is a Butia palm native to southern Brazil, Uruguay and northern Argentina. It is known as the butiá-jataí in Portuguese in the south of Brazil, as well as simply jataí or butiá. It is sometimes cultivated as an ornamental in Europe and the United States. It is the tallest of all the species in the genus Butia. The fruit is edible with a sweet flavour. Etymology This is one of only a few plants in which the scientific name is completely derived from Native American languages. Butia is from a local Brazilian vernacular name likely derived from Old Tupi ᵐba atí, meaning 'thorny thing', which probably refers to the spines along the petiole margins of most species. The specific epithet yatay is adopted from the Guaraní language word for such palms, yata'i, which itself refers to the small, hard fruit. Taxonomy In 1970 Sidney Fredrick Glassman moved this species, along with all other Butia, to Syagrus, but in 1979 he changed his mind and moved everything back. A population of Butia palms growing in Paraguay known as B. dyerana was synonymised with this species by Glassman, but this population was reclassified as a synonym of B. paraguayensis by at least 1996, removing B. yatay from the flora of Paraguay. B. poni (Hauman) Burret [1930] (syn. Cocos poni Hauman [1919], a nomen nudum) was considered a synonym of B. yatay (and B. paraguayensis, pro parte, fide Soares [2015]), but was recognised as a species in its own right in 2017 by Deble after he rediscovered a population of the species in Argentina and was able to confirm its distinctiveness. The recent taxa B. missionera and B. quaraimana described by Deble & Marchiori from Rio Grande do Sul, Brazil, and B. noblickii described by Deble from a population of palms in Corrientes Province of Argentina, have all been synonymised with this species either by Soares et al. in 2014, or Soares in 2015. Description This is a solitary-trunked palm; the trunk often grows at an incline and is from 3 to 16m, exceptionally 18m tall, although they usually grow shorter in Brazil (to 8m). The trunks grow from 30 to 55 cm in diameter, usually retaining a coat of old leaf bases which do not shed easily naturally and which remain persistent for many years. Leaves There are 11 to 31 pinnate leaves arranged