Heliotropium curassavicum var. argentinum and var. H. curassavicum have been investigated chemically and a new pyrrolizidine alkaloid has been isolated from both. The latter variety also yielded a related acetylated, 9-(3′-isovaleryl)viridifloryl retronecine alkaloid. The structures have been established by spectroscopic means. Trachelanthamidine was the dominant base found in previous studies of H. curassavicum whereas retronecine is the necine present in the alkaloids now reported. © 1988.