Taxonomy of the Chelone obliqua (Plantaginaceae) Polyploid Complex
Nelson A. 2024. Taxonomy of the Chelone obliqua (Plantaginaceae) Polyploid Complex. Phytoneuron. :1-8
ABSTRACT: Chelone obliqua L. sensu lato is treated here as three separate species –– Chelone obliqua L., Chelone erwiniae (Penn. & Wherry) A.D. Nelson comb. et stat. nov., and Chelone speciosa (Penn. & Wherry) A.D. Nelson comb. et stat. nov. The three species differ in sepal ciliation and mid-cauline leaf length and width. Chelone obliqua and C. speciosa are hexaploid; C. erwiniae is tetraploid. Each new species occurs in a distinct ecoregion at a distinct elevation. Isozyme and DNA data indicate independent evolutionary origins of each of the three polyploid species. Tetraploids are found in the southern Blue Ridge and surrounding highlands whereas hexaploids are in the Midwestern Central Lowland and the Atlantic Coastal Plain. Within each of these three ecoregions, distinct genotypes occur due to different polyploid speciation events as supported by unique isozyme and DNA markers.