International journal of plant sciences vol:171 issue:4 pages:421-434
Recent molecular investigations have greatly improved our understanding of the phylogenetic relationships of the Valeriana clade. Our investigation of the fruits and seeds of the Valeriana clade provides morphological support for these findings. In particular, seed anatomy, calyx morphology, the presence of sterile locules, and fruit polymorphism provide support for the major lineages in the Valeriana clade (i.e., Valerianaceae). Fruit and seed morphology and anatomy of all genera but Nardostachys were investigated. Our results indicate that an important shift in seed anatomy took place at the origin of the core valerians (i.e., Valerianeae), including the loss of endosperm and a shift in seed coat anatomy. Furthermore, our data suggest that the evolution toward polymorphic fruits occurred at least twice, once at the origin of the clade holding Fedia and Valerianella and a second time at the inception of Plectritis. Our sampling indicates that the loss of sterile locules in mature achenes took place along the branch leading to Centranthus, Plectritis, and Valeriana. To confirm this, it will be necessary to examine South and Central American Valeriana species.