FLORAL ODORS IN THE THEOPHRASTACEAE

Floral scent was collected by head-space adsorption from seven species of the Theophrastaceae, viz Theophrasta americana, Deherainia smaragdina, Jacquinia keyensis, J. macrocarpa, J. sprucei, Clavija euerganea and C repanda. The chemical composition of the floral scent was determined with coupled gas chromatography-mass spectrometry (GC-MS). The floral scent composition accord with the generic delimitation within the Theophrastaceae; Theophrasta is characterized by a fatty acid derived alcohol and an acid, Deherainia by fatty acid derived esters and an acid, and pyrazines, Jacquinia by benzenoids and phenyl propanoids with additionally trimethylcyclohexanes-derivatives of carotenoids in the orange-flowered species (J. macrocarpa, J. sprucei), and Clavija mainly by sesquiterpene hydrocarbons. We suggest that the trimethylcyclohexenes in the floral scent of the orange-flowered Jacquinia species are formed during anthesis through degradation of carotenoids in the corolla pigments. Floral morphology and scent chemistry suggest that Theophrasta and Deherainia are sapromyophilous, while Jacquinia and Clavija are melittophilous. Melittophily is suggested to be the ancient condition in the family, while the derived condition, sapromyophily, may have evolved independently in Deherainia and Theophrasta.