LSA can be found in many plant species. Among these are:

Argyreia nervosa

Ipomoea corymbosa

Ipomoea tricolor

Albert Hoffman: “It is perhaps no coincidence but of deeper biological significance that of the four possible isomers of LSD, only one, which corresponds to natural lysergic acid, causes pronounced mental effects. Evidently, the mental functions of the human organism, like its bodily functions, are particularly sensitive to those substances which possess the same configuration as naturally occurring compounds of the vegetable kingdom.”