In 1997 and 1998,[58][59] researchers at Texas A&M University claimed to have found amphetamine and methamphetamine in the foliage of two Acacia species native to Texas, A. berlandieri and A. rigidula. Previously, both of these compounds had been thought to be human inventions. These findings have never been duplicated, and the analyses are believed by many biochemists to be the result of experimental error, and as such the validity of the report has come into question. Alexander Shulgin, one of the most experienced biochemical investigators and the discoverer of many new psychotropic substances, has tried to contact the Texas A&M researchers and verify their findings. The authors of the paper have not responded; natural amphetamine remains an unconfirmed discovery.[60]
