The morphogenesis of the inflorescences and flowers of Rhynchoglossum omeiense has been observed and compared with its allied groups. Several remarkable features and evolutionary trends have been revealed as the followings : 1) The inflorescence meristem of R. omeiense is different from the normal racemose meristem in its fusiform and ellipsoid apices having been shifted to the ventral side of the axis instead of globose apices on the top of axis in the normal raceme, which has developed a unilateral raceme with only two ventral rows of bracts bearing flowers. 2) The bilabiate corolla and didynamous stamens in this species is probably related to the state of suppression of the staminode. 3) The initiation and early development of its gynoecium has maintained the nature of the carpellary closure which may have formed the axile placentation in its ancestral group. The bilocular ovary at the early developmental stage gradually transforms into unilocular one in the following developmental process. 4) As a relict species of the Klugioid plants, it is close to the genus Whytockia. However, it is almost impossible that R .omeiense has been evolved from Whytockia, but that Klugia and Whytockia may have come from a common ancestor and developed in different ways.
Floral Morphogenesis of Rhynchoglossum omeiense (Gesneriaceae) and Its Phylogenetic Implication
Publication: Acta Botanica Yunnanica