There are many discussions about taxonomic position of Linum glaucum in different Flora. In this study, the morphological traits associated with the nuclear genome size were used for identification of infraspecific variations in the nine populations of L. glaucum. Twenty three qualitative and quantitative morphological characteristics were investigated. The Analysis of variance tests showed significant difference for some morphological features. The Canonical Correspondence Analysis of habitat ecological factors showed that each of the habitats had prominent characteristics, and also Pearson’s coefficient of correlation confirmed the significant correlations between the morphological features in relation to ecological factors. In the morphological Unweighted Paired Group using Average method tree, populations were separated from each other, so that population No. 4 was separated from others. In the flow cytometery investigations, variation of about 1.19 times was presented between the maximum and minimum averages of the genome sizes in the populations. Minimum amount of genome size was found in populations No. 4. Significant correlations occurred between the nuclear genome size with habitat elevation as well as some of the quantitative morphological features. The mentioned variations caused to difference between the populations and lead to creation of ecotype and ecophene in the studied populations.
