The three earliest extant lineages of flowering plants are represented by only some 16 genera. Despite low species’ diversity, these genera are highly diverse in their morphology, so inferring ancestral features in angiosperms is problematic. Using SEM, TEM and immunocytochemistry , Prychid et al. investigate the reporoductive structures of a relatively newly discovered early angiosperm, Trithuria (Hydatellaceae). The presence of a dry-type stigma in Trithuria supports the hypothesis that this condition is ancestral in angiosperms.
