Study of the polymorphism of the Patagonian Calceolaria polyrhiza(Calceolariaceae) using decision tree and sequential covering rule induction

Abstract

Climate and landscape changes that occurred in Patagonia during the Pleistocene presumably led to the ample biodiversity that currently characterizes the region. Many Patagonian species constitute unresolved complexes that may be related to these environmental changes. Accordingly, discriminating among taxonomic entities within an endemic and widely distributed species in Patagonia would enable a better understanding of the diversification processes that occurred in the recent past. We explored the polymorphism ofCalceolaria polyrhiza,a widely distributed species for which phylogeographic studies suggest a recent diversification, with the aim of disentangling the morphological variability patterns in this species. We employed quantitative and qualitative floral and vegetative traits, including geometric morphometric variables. We used two clustering algorithms, testing for correspondence between detected clusters and the species previously described for the complex. Finally, we described these clusters using decision trees and sequential covering rule induction. Major clusters were deter-mined, which match the previously described species. Floral traits related to corolla design and shape were the most useful characters for distinguishing groups and the variation patterns in these traits might be associated with historical and ecological factors. The need for conducting plant systematic studies using techniques that ensure objective taxonomic delimitations and descriptions is stressed.