Evolution of flower shape in Veroniceae (Scrophulariaceae)

Floral evolution in the tribe Veroniceae was examined using phylogenetic analysis combining 24 adult morphology and chromosome number characters with 22 qualitative and quantitative floral development characters. Taxa sampled included nine species of Veroniceae and as an outgroup one species each of Digitaleae and Verbasceae. Veronica, Besseya, and Synthyris formed one clade, subtended by Pseudolysimachion and then by the Hebe group; Veronicastrum or Wulfenia represent the basal-most branch of the tribe. The ancestral flowers of the Veroniceae may have been small with moderately short corolla tubes and lobes; long corolla tubes arose four times in the tribe and large corolla lobes twice.