Linanthus Research Articles

Towards A Complete Species Level Phylogeny of Leptosiphon (Polemoniaceae)

Abstract Leptosiphon Benth. (Polemoniaceae) has 40 taxa, distributed mainly in western North America, with one species in Chile. Phylogenetic studies of Polemoniaceae have consistently supported recognition of Leptosiphon as a separate genus from Linanthus, and resolved an array of taxonomic problems; however, several issues remained unclear for Leptosiphon. In those studies, sampling of Leptosiphon was incomplete, and certain species having strikingly similar floral morphologies appeared non-monophyletic, while other species groups with divergent floral morphologies formed a clade. Our analyses use greater sampling across taxa in Leptosiphon and, in addition to nrITS, the non-coding chloroplast region trnS–trnG to help resolve the genus phylogeny. These results yielded a more complete phylogeny from which to base further research on floral evolution in this group. However, much work remains to be done in resolving species level relationships. Analyses of morphological character evolution suggest that sev...

Evidence for Polyphyly in a Species of Linanthus (Polemoniaceae): Convergent Evolution in Self-Fertilizing Taxa

Abstract Sequence data for the ITS region of rDNA provide evidence that Linanthus bicolor, an annual species of western North America, is polyphyletic. A previous study identified two sequence types, distinguished by over 50 fixed nucleotide differences, in populations from different geographical regions. Phylogenetic analysis revealed that the two are not sister taxa and, furthermore, that each represents an independent origin of self-fertilization. The morphological similarity of the two taxa, especially in floral traits, is hypothesized to have resulted from convergent evolution in characters associated with self-fertilization. Morphological and genetic data for populations sampled throughout the range of L. bicolor indicate that these distinct genetic types correspond to intraspecific taxa as currently circumscribed. The molecular evidence for polyphyly of L. bicolor, presence of significant morphological differences between the two taxa, and evidence that they are, to a large extent, reproductively i...

Remarks on the Genus Linanthus

Remarks on the Genus Linanthus