Wells diagram of Aquilegia samples. The red circles are the reference population of A. formosa, and the yellow circles are the reference population of A. flavescens. The black triangles denote type specimens, with the blue triangle indicating the holotype. The outer semicircle connects the two reference extremes on the x-axis, whereas the inner semicircle encloses all the parental specimens (except one outlier). The type specimens occupy an intermediate position, although skewed towards and intergrading with A. flavescens. The type specimens are also all within the inner semicircle, satisfying the theoretical expectations of intermediacy. The numerical position on the x-axis is the Wells Index (as given in Table 1).