Dahlia barkerae Knowles & Westc. Dahlia barkerae Knowles & Westc., Fl. Cab. 2: 28. 1838 sec. Carrasco-Ortíz & al. 2019=Dahlia scapigera var. arsenei Sherff in Amer. J. Bot. 33: 508. 1946 syn. sec. ???