Floral scent of snapdragon flowers is dominated by two isoprenoids, the monoterpene olefins myrcene and (E)- -ocimene, which are derived from geranyl diphosphate, and a phenylpropanoid aromatic ester, methylbenzoate. Dudareva et al. (pp. 1227–1241) show that emissions of the monoterpene compounds follow similar diurnal rhythms that are controlled by the circadian clock and require the presence of specialized monoterpene synthases. The newly isolated snapdragon monoterpene synthases define a new subfamily of terpene synthases designated as the Tps-g group. Analyses of tissue-specific, developmental, and rhythmic expression of the genes encoding these monoterpene synthases revealed that the composite floral scent bouquet in snapdragon is regulated at a level upstream of individual metabolic pathways, thus coordinating emission of phenylpropanoids and isoprenoids.