Phylogenetic placement of the enigmatic genus Holocheila (Lamiaceae) inferred from plastid DNA sequences

Abstract

The monotypic genus Holocheila was originally placed in Teucrium sect. Holocheila but was later treated as a distinct genus and variably affiliated with subfamilies Ajugoideae, Scutellarioideae, or Lamioideae. We investigated the phylogenetic position of this enigmatic genus using likelihood, parsimony, and Bayesian methods based on six plastid DNA sequences. The preliminary results from a concatenated ndhF and rbcL dataset that covered all seven subfamilies of Lamiaceae suggested that Holocheila is part of subfamily Lamioideae. To examine its position within Lamioideae more thoroughly, a dataset was assembled that included representatives of 59 of the 63 genera of Lamioideae and data for four genetic markers: trnL intron, trnL‐trnF spacer, rps16 and matK. The results showed that Holocheila is part of tribe Pogostemoneae. Glossy mericarps and unilocular anthers are apomorphies that Holocheila shares with some members of Pogostemoneae. The genera Acrymia and Cymaria, which have been considered incertae sedis, were found to be the closest relatives of Lamioideae. Four other incertae sedis genera (Garrettia, Hymenopyramis, Peronema, Petraeovitex) appear to form a clade that is sister to the clade comprising Lamioideae, Acrymia, Cymaria, and Scutellarioideae.

Phylogeny of non‐monophyletic Teucrium (Lamiaceae: Ajugoideae): Implications for character evolution and taxonomy

“…In addition, several groups within the Lamiaceae have recently been subjected to divergence time estimates (e.g., Drew & Sytsma, 2012Roy & Lindqvist, 2013;Yu & al., 2014). Since the close relationship between Ajugoideae and Lamioideae was confirmed by Chen & al. (2014), we used two calibration points based on a previous investigation of subfamily Lamioideae by Roy & Lindqvist (2015).…”

Resolving the phylogenetic position of Ombrocharis (Lamiaceae), with reference to the molecular phylogeny of tribe Elsholtzieae

“…The taxon sampling and choice of markers were largely in accord with the previous framework of Li & al. (2012) and Chen & al. (2014), with the major differences being our outgroup sampling and the inclusion here of three genera of incertae sedis, Ombrocharis, Tectona, and Callicarpa.…”

“…Based on results from a recent Lamiales-wide study by Refulio-Rodriguez & Olmstead (2014) , as well as eight genera treated by as incertae sedis with respect to subfamily (all such genera of Lamiaceae except Acrymia and Garrettia). Eight sequences for the two plastid DNA (cpDNA) markers were newly sequenced (three rbcL, five ndhF), while other data were taken from our previous studies (Li & al., 2012;Chen & al., 2014) or downloaded from GenBank (see Appendix 1). We used the phylogenetic results from this first set of analyses as a basis for a more focused second round of analyses.…”

“…For the PCR amplification of rbcL, primers Z1F and Z1351R (Soltis & al., 1992) were used. The PCR reaction mixtures and program for rbcL followed Chen & al. (2014).…”

“…The phylogenetic framework of Lamiaceae (Fig. 3) resulting from the concatenated rbcL and ndhF dataset is largely consistent with previous studies (Li & al., 2012;Chen & al., 2014). Lamiaceae are strongly supported as monophyletic (BI-PP = 1.00/MP-BS = 100%/ML-BS = 100%; all values follow this order hereafter), although relationships within the family are not well resolved.…”