Phylogeny and biogeography of the northern temperate genus Dracocephalum s.l. (Lamiaceae).

The northern temperate genus Dracocephalum consists of approximately 70 species mainly distributed in the steppe-desert biomes of Central and West Asia and the alpine region of the Qinghai-Tibetan Plateau (QTP). Previous work has shown that Dracocephalum is not monophyletic and might include Hyssopus and Lallemantia. This study attempts to clarify the phylogenetic relationships, diversification patterns, and the biogeographical history of the three genera (defined as Dracocephalum s.l.). Based on a sampling of 66 taxa comprising more than 80% from extant species of Dracocephalum s.l., morphological, phylogenetic (maximum parsimony, likelihood, and Bayesian inference based on nuclear ITS and ETS, plastid rpl32-trnL, trnL-trnF, ycf1, and ycf1-rps15, and two low-copy nuclear markers AT3G09060 and AT1G09680), molecular dating, diversification, and ancestral range estimation analyses were carried out. Our results demonstrate that both Hyssopus and Lallemantia are embedded within Dracocephalum and nine well-supported clades can be recognized within Dracocephalum s.l. Analyses of divergence times suggest that the genus experienced an early rapid radiation during the middle to late Miocene with major lineages diversifying within a relatively narrow timescale. Ancestral area reconstruction analyses indicate that Dracocephalum s.l. originated in Central and West Asia and southern Siberia, and dispersed from Central and West Asia into the QTP and adjacent areas twice independently during the Pliocene. The aridification of the Asian interior possibly promoted the rapid radiation of Dracocephalum within this region, and the uplift of the QTP appears to have triggered the dispersal and recent rapid diversification of the genus in the QTP and adjacent regions. Combining molecular phylogenetic and morphological evidence, a revised infrageneric classification of Dracocephalum s.l. is proposed, which recognizes nine sections within the genus.

The complete chloroplast genome of Phlomoides betonicoides (Lamiaceae), a traditional Tibetan medicinal herb.

The species Phlomoides betonicoides is used medicinally and mainly distributed in southwest China. The first complete plastid genome sequence of P. betonicoides reported here was 151,777 bp long, with the large single copy (LSC) region of 83,205 bp, the small single copy (SSC) region of 17,370 bp and two inverted repeats (IRa and IRb) of 25,601 bp. The plastome contained 114 genes, including 80 protein-coding genes, four ribosomal RNA genes, and 30 transfer RNA genes. The overall GC content was 38.5%. Result from phylogenetic analysis suggests that tribe Phlomideae (Phlomoides) is closely related to tribe Lamieae and tribe Leonureae in present study.