Epidermal Features and Spikelet Micromorphology in 'Oryza' and Related Genera(Poaceae: Oryzeae)

摘要

Using scanning electron microscopy, this study examines the spikelet morphologyof sixteen species of Oryza, one species of leersia, and one species each of the monotypic genera Porteresia and Rhynchoryza. A detailed discussion of the spikelet epidermal features and their relationship to the pedicel and cupule is presented. As the pedicel and cupule of species of Oryza are below the point of articulation of the spikelet, have similar epidermal features and are free from the vascular cylinder that proceeds upward (distally) into the spikelet, we conclude that the pedicel cupules are not glumes but are merely expanded apices of he pedicels. An original data set of 14 morphological characters was used to perform parsimony and UPGMA analyses. Of these 14 characters, six describe the lemma, three describe the rachilla, two describe the glumes, two describe the articulation point and callus shape, and one describes the embryo.