Molecular phylogeny of Nanophyton L. (Chenopodioideae): emphasis on the similar species N. erinaceum and N. mongolicum

Abstract

Nanophyton L. has been treated as a monotypic genus, but seven other Nanophyton species have been published based on morphological features. To examine the phylogenetic relationships between Nanophyton species, especially the similar species N. erinaceum and N. mongolicum, all species in Nanophyton except N. pulvinatum and different populations of N. erinaceum and N. mongolicum in China were sampled from herbarium specimens. Samples were analyzed based on two molecular markers (ITS and psbB‐psbH) using maximum likelihood and Bayesian inference methods. Our results provided support for the following conclusions: 1) Nanophyton is monophyletic and composed of two monophyletic clades. One clade may be recognized as N. sect. Nanophyton, but contrary to the current taxonomy it includes only N. erinaceum. The other clade represent N. sect. Montana and include all other Nanophyton species, but intragenetic variation within this clade is low. 2) Variable sites in both ITS and psbB‐psbH sequences well distinguish N. erinaceum from N. mongolicum, and samples from different populations of N. erinaceum and N. mongolicum in China formed well‐supported, distinct clades. 3) Nanophyton erinaceum is a typical Central Asian species, mainly distributed in western Siberia and Central Asia (Kazakhstan, Kyrgyzstan, Tajikistan, Mongolia and northwestern China (north Xinjiang)), while N. mongolicum is a Mongolian floristic element species mainly found from the Altai region of northern Xinjiang (China) to Mongolian Altai (Mongolia).