Mattiastrum pulumurense (Cynoglossinae, Boraginaceae), a new endemic species from Türkiye

A new species, Mattiastrum pulumurense, has been described from Tunceli in eastern Türkiye. It is generally distinguished from other species (except M. racemosum var. scabridum) by a sparsely hairy or glabrescent above-ground part. It is most similar morphologically to M. longipes, M. calycinum, and Paracaryum hedgei (P. hedgei is potentially a member of the genus Mattiastrum). However, it differs from M. longipes and M. calycinum by its 3–3.5-mm-long and linear lanceolate scales, 2.5–4.5-mm-long anthers, and 10–15-mm-long styles; it differs from Paracaryum hedgei by its 3–3.5-mm-long scales, 2.5–4.5-mm-long anthers. In addition, this new species differs from M. racemosum var. scabridum by having 3–3.5-mm-long scales and no scale appendages. A description of the new species, an illustration, a comparative Table of morphological characters, detailed photographs, and a distribution map of the new species together with adjacent species were provided. In addition, the evolutionary relationships of these species were calculated using both Bayesian inference and maximum likelihood analyses based on the ribosomal internal transcribed spacer (ITS1-5.8S-ITS2) and combined chloroplast data set (rps16 and trnL genes, trnL-trnF intergenic spacer). According to the phylogeny-based combined chloroplast data set, both populations of Mattiastrum pulumurense generate a monophyletic clade and are closely related to M. longipes, P. hedgei, and M. calycinum. According to ITS-based phylogeny, Mattiastrum pulumurense is closely related to Rindera tetraspis, which is seen in the paraphyletic and nested genera Mattiastrum-Paracaryum-Rindera.