2-Methyl-1,2,3,4-tetrahydro-β-carboline was isolated from reed canarygrass (Phalaris arundinacea L.) and the occurrence of 2-methyl-6-methoxy-1,2,3,4-tetrahydro-β-carboline confirmed. Clones of reed canarygrass that contained N,N-dimethyltryptamine or 2-methyl-1,2,3,4-tetrahydro-β-carboline did not contain their respective methoxy or hydroxy derivatives. Five of the 12 clones tested contained either or both of 5-methoxy-N,N-dimethyltryptamine and 2-methyl-6-methoxy-1,2,3,4-tetrahydro-β-carboline. The data suggest that clones that contain gramine are not likely to contain N,N-dimethyltryptamine and/or β-carbolines. Thus, an inverse biosynthetic relationship between gramine and the tryptamine and β-carboline alkaloids seems to exist. However, further work is needed to firmly establish any such relationship between these alkaloids.