Another historical milestone is the discovery of DMT in plants frequently used by Amazonian natives as additive to the vine "Banisteriopsis caapi" to make ayahuasca decoctions. In 1957, American chemists Francis Hochstein and Anita Paradies identified DMT in an "aqueous extract" of leaves of a plant they named "Prestonia amazonicum" ["sic"] and described as "commonly mixed" with "B. caapi". The lack of a proper botanical identification of "Prestonia amazonica" in this study led American ethnobotanist Richard Evans Schultes (1915–2001) and other scientists to raise serious doubts about the claimed plant identity. The mistake likely led the writer William Burroughs to regard the DMT he experimented with in Tangier in 1961 as "Prestonia". Better evidence was produced in 1965 by French pharmacologist Jacques Poisson, who isolated DMT as a sole alkaloid from leaves, provided and used by Agaruna Indians, identified as having come from the vine "Diplopterys cabrerana" (then known as "Banisteriopsis rusbyana"). Published in 1970, the first identification of DMT in the plant "Psychotria viridis", another common additive of ayahuasca, was made by a team of American researchers led by pharmacologist Ara der Marderosian. Not only did they detect DMT in leaves of "P. viridis" obtained from Kaxinawá indigenous people, but they also were the first to identify it in a sample of an ayahuasca decoction, prepared by the same indigenous people.