Edaphic races and phylogenetic taxa in the Lasthenia californica complex (Asteraceae: Heliantheae): an hypothesis of parallel evolution


Nishanta Rajakaruna. ¶Present address: Department of Biological Sciences, 371 Serra Mall, Stanford University, Stanford, CA 94305–5020, USA. Fax: 650–723–6132; E-mail: nishanta@stanford.edu


Lasthenia californica sensu Ornduff consists of two races that differ in their flavonoid pigments and edaphic tolerances. Recent phylogenetic studies of Lasthenia have revealed that members of L. californica sensu Ornduff belong to two phylogenetic species. The relationship of the edaphic races to these new species and to each other is the focus of this study. Characterization of flavonoid profiles and phylogenetic placement of 33 populations demonstrates that races and phylogenetic taxa are not concordant, suggesting that one or both edaphic races evolved in parallel in the two clades. We hypothesize an edaphically linked ecological role for flavonoid differences that first revealed the existence of two races.