Molecular Phylogenetic Evidence and Biogeographic History of Indian Endemic Portulaca L. (Portulacaceae) Species

The genus Portulaca L. belongs to the monogeneric family Portulacaceae and consists of about 157 species worldwide. In India, it is represented by 11 taxa; among them, Portulaca badamica, Portulaca lakshminarasimhaniana, Portulaca oleracea var. linearifolia, and Portulaca laljii are endemic. So far, the phylogenetic positions of these species have not yet been analyzed. We have reconstructed the Bayesian and maximum likelihood phylogenies based on a combined chloroplast and nuclear DNA sequence dataset to reveal phylogenetic placements of Indian Portulaca. Phylogenetic analyses indicate that all the sampled Indian Portulaca species (except Portulaca wightiana) are placed in the AL clade, which contains most of the known species of the family Portulacaceae. We used reconstructed phylogeny to study the historical biogeography of Indian endemic species by employing S-DIVA analysis. S-DIVA analysis suggested P. lakshminarasimhaniana has origin in India, it may be the result of in situ speciation in India, and P. badamica was dispersed from Africa to India. We have also discussed the systematic placements of endemic species and their morphological relationships with closely allied species. In addition, this study also provides taxonomic treatment for endemic species.