Abstract
Coumarin and herniarin are formed in lavender from labeled o - and p -coumaric acids, respectively. At least part of the herniarin exists in lavender as a glycoside, presumably a 4-methoxycoumarinic acid glycoside, which yields free herniarin on hydrolysis. Biosynthesis of herniarin by successive para - and ortho - hydroxylation of cinnamic acid is indicated.