Phylogenetic studies in Smallanthus Mack. (Millerieae, Asteraceae), a contribution from morphology.

Abstract

We present a cladistic analysis of all the species of Smallanthus. Six taxa within Rumfordia, Ichthyothere, Acanthospermum and Tridax served as outgroups. We evaluated the monophyly and the relationships between the species of Smallanthus through a maximum parsimony study based on morphological data. The matrix included 31 qualitative characters from floral and vegetative parts of the specimens. We also explored the phylogenetic significance of treating quantitative characters as continuous. Only one most parsimonious tree was obtained. In agreement with previous phylogenetic studies based on molecular data, we recovered a monophyletic Smallanthus. The presence of ray corollas, densely pubescent at the base, was the synapomorphy that defined Smallanthus. Smallanthus microcephalus and two other major clades were recovered. The first clade included S. glabratus, S. fruticosus, S. jelskii and S. pyramidalis, while the second one contained the remaining species of Smallanthus. The analysis recovered one species of Rumfordia as sister to Smallanthus. We present a new combination, Smallanthus cocuyensis, based on morphological analysis of the type specimen.