Phylogenetic Analysis Of Ddradseq Data Reveals the Little mousetail (Myosurus Minimus Subsp. Apus) to Be a Rare Species Restrict

Reduced-representation genomic sequencing (ddRADseq) is a cost-effective method providing answers to long-standing questions about fine-scale plant diversity, with implications for conservation and management of rare species. In this study, we used population-level sampling and ddRADseq to carry forward a phylogenetic analysis of vernal-pool mousetails (Myosurus) in California. A specific objective was to test if there is a genetic basis for recognizing the little mousetail (M. minimus subsp. apus) as a distinct taxon. This plant has had a California Rare Plant Rank of 3 (“more information needed”) in the CNPS Rare Plant Inventory since 1988 and had not been studied until now. Results indicate that the little mousetail is not very closely related to European M. minimus and should instead be recognized as a separate species (M. apus) restricted to coastal southern California and adjacent Baja California. Also to be described and named are two new Myosurus species (previously confused with M. apus) from California’s Central Valley. Due to a gap in sampling, the appropriate taxonomic placement of plants from Riverside County remains unknown. The different and often confusing morphotypes seen in Central Valley Myosurus populations are best explained not by hybridization but rather by the presence of previously unrecognized species, together with inherent within-species variability.