REPRODUCTIVE MORPHOLOGY OF QUERCUS (FAGACEAE)

Abstract

Details of inflorescence, floral, and fruit morphology have been studied in more than 120 species of Asiatic and American Quercus. Of the two subgenera, subgenus Cyclobalanopsis has fewer species but greater diversity of reproductive morphology than subgenus Quercus. Some character states of subgenus Cyclobalanopsis, such as more numerous stamens, male flowers sometimes grouped in dichasia, abortive ovules well developed, prominent intrusive septae in the nut, and lamellate cupules, are shared with Lithocarpus. The diversity of cupular sizes, coverage, and ornamentation raises questions about the adaptive nature, ecological function, and phylogeny of the cupule, which clearly has by now evolved as a structure with its own qualities.