prestonia amazonica prestonia amazonica prestonia amazonica is a hallucinogenic plant native to the amazon rainforest. this plant is cited in louisiana state act 159. prestonia amazonica scientific classification kingdom: plantae clade: tracheophytes clade: angiosperms clade: eudicots clade: asterids order: gentianales family: apocynaceae genus: prestonia species: p. amazonica binomial name prestonia amazonicaj.f.macbr. synonyms haemadictyon amazonicum benth. ex müll.arg.