Grasses of the genus Phalaris seem to show wide variations in the nature and quantity of the indole derivatives present in selected strains grown as pasture in different places. We have now found that five strains of Phalaris tuberosa L. grown in one locality in South Australia consistently contain, as minor constituents at all stages of growth, 2-methyl-1,2,3,4-tetrahydro-beta-carboline and 6-methoxy2-methyl-1,2,3,4-tetrahydro-beta-carboline.