The phylogeny of members of the family Linaceae DC. ex Perleb has not been adequately studied. In particular, data on the phylogenetic relationship between Linum stelleroides Planch. and other representatives of the blue-flowered flax are very controversial. In the present work, to clarify this issue, we obtained DNA sequences of three nuclear loci (IGS and ITS1 + 5.8S rDNA + ITS2 of the 35S rRNA gene and the 5S rRNA gene) and eight chloroplast loci (rbcL, the trnL–trnF intergenic spacer, matK, the 3′ trnK intron, ndhF, trnG, the psbA–trnH intergenic spacer, and rpl16) of 10 Linum L. species (L. stelleroides, L. hirsutum, L. perenne, L. leonii, L. lewisii, L. narbonense, L. decumbens, L. grandiflorum, L. bienne (syn. L. angustifolium), and L. usitatissimum) using high-throughput sequencing data. The phylogenetic analysis showed that L. stelleroides forms a basal branch in the blue-flowered flax clade. Previously found inconsistencies in the position of L. stelleroides and some other species in the Linaceae phylogenetic tree resulted from the erroneous species identification of some of the studied plant samples.
