Two new ergot alkaloids belonging to the ergopeptine class have been found in saprophytic cultures of strain 231 F.I. of Claviceps purpurea that produces mainly ergotoxine. They have an additional methyl group in the peptide side chain and correspond to O(12')-methylergocornine [1] and O-12'-methyl-α-ergokryptine {2}. Their structures have been assigned on the basis of spectral data, amino acid composition, and degradation procedures. The involvement of these alkaloids in the biosynthesis of ergopeptines, as suggested by their fragmentation pattern in eims, is discussed, and a possible biosynthetic scheme is proposed. © 1987, American Chemical Society. All rights reserved.