The structure of 10-epi-lyfoline [6], a biphenylquinolizidine alkaloid isolated from Heimia montana, has been established by nmr studies. The presumed structure of lyfoline [4] has been confirmed. Heimia montana (Griseb.) Lillo (Lythraceae) has been shown to elaborate several related biphenylquinolizidine alkaloids that are also found in other plants of the genus (1). Vertine [1], heimidine [2], lythrine [3], lyfoline [4], and lythridine [5], have all been identified from the plant, and, as can be seen from the structures, with the exception of 4, the alkaloids exist as diastereomeric pairs differing only in the stereochemistry at C-10. We wish to report herein on the structure of the previously unreported 10-epi-lyfoline [6], and to present evidence which confirms the long-assumed structure of lyfoline [4].