Schlumpberger B. O., Renner S. S., Molecular phylogenetics of Echinopsis (Cactaceae): Polyphyly at all levels and convergent evolution of pollination modes and growth forms, American Journal of Botany, 2012, 99(8):1335-1349, doi: 10.3732/ajb.1100288
The supplied full text was read. The plastid analysis informs the genus account. The scan of Table 3 was checked for A. spiniflorum and A. thionanthum, distinguishing chromosome counts from population sample sizes.