Mating system, morphological, and genetic evidence endorse clonality as an essential reproductive mode in Daphnopsis filipedunculata (Thymelaeaceae), a dioecious and endemic species from the Amazon

Background and Aims Clonality is characterized by the formation of independent individuals of the same genotype that are capable of reproducing and propagating vegetatively. Although clonality is an important mechanism that facilitates the persistence of a population, its extensive use can lead to negative impacts on sexual reproduction due to trade-offs in the investment of resources. Therefore, studies on the sexual reproduction of species that exhibit clonality can provide information about resilience to environmental changes, information about fecundity, the risk of the absence of pollinators, and the ability to persist in unfavorable conditions and to successfully occupy new areas. Here, we investigated the role of clonal propagation and sexual reproduction in Daphnopsis filipedunculata (Thymelaeaceae), a dioecious species distributed only in Serra dos Carajás. Methods We evaluated the extent of clonality in this species using molecular tools and anatomical analyses of the underground system responsible for developing new ramets. Furthermore, we analyzed the sexual system and its contribution to reproductive success through morphometric analyses of floral types and pollination experiments in the field. Key Results Overall, we found that clonal propagation plays an important role in maintaining the population of D. filipedunculata. Specifically, we demonstrated that this species presents functional male and female plants, indicating that D. filipedunculata is an obligate xenogamous species but has low reproductive success. We also showed that clonal vegetative propagation is the main form of asexual reproduction in this species, with roots responsible for clonal growth. Finally, our results indicated that this species presents an intermediate phalanx-guerrilla clonal architecture. Conclusions Our study provides the first insights into sexual reproduction and clonal propagation in D. filipedunculata and can inform management practices, conservation, and the restoration of endemic species.