Phylogenetic analysis of the genus Stachys sect. Eriostomum (Lamiaceae) in Turkey based on nuclear ribosomal ITS sequences

Abstract

Morphological revision and phylogenetic analysis of Stachys L. sect. Eriostomum (Hoffmanns. & Link) Dumort. (Lamiaceae) based on nuclear ribosomal internal transcribed spacer (nrITS) sequences were conducted. Morphological analysis confirmed the previous arrangements of 3 subsections, i.e. Germanicae R.Bhattacharjee, Creticae R.Bhattacharjee, and Spectabiles R.Bhattacharjee, while suggesting some status changes and new records that were also confirmed by the phylogenetic analysis. The phylogenetic analysis suggested, however, some arrangements different from those indicated by morphology. Two subsections, i.e. Creticae and Germanicae-Spectabiles, instead of 3 were observed in the phylogenetic tree. The tree also suggested that 9 Stachys cretica L. subspecies form a polyphyletic rather than a monophyletic group. While at least 2 clades were clearly identified in the subsection Creticae, no meaningful clades in the subsection Germanicae-Spectabiles were detected in the tree. Flower colour and altitude were not represented by any difference in nrITS DNA sequence of the taxa examined, while 2 distant populations of Stachys spectabilis Choisy ex DC. differed in that respect. A potentially new species of Stachys was observed in the tree. The tree clearly displayed the monophyly of Eriostomum, while confirming the recently suggested new status (as a genus) of the subgenus Betonica (L.) R.Bhattacharjee.