The aerial parts of Montana hibiscifolia afforded, in addition to known compounds, twelve new germacranolides, all being 6, 12-cis-lactones, as well as a new types of sesquiterpene lactone, obviously closely related to one of the germacranolides. Furthermore, a new prostaglandin-like compound was found together with one previously known. From Montanoa dumicola two 6,12 cis-germacranolides, as well as two 6,12 cis-eudesmanolides and geranyl phloracetophenone derivative, were isolated, The structures and the stereochemistry of all compounds were elucidated by their pmr spectral data. Biogeneric relationships are discussed briefly.
