Linum is one of the most useful genera of Linaceae widely distributed in different parts of Iran. In the present study, petal flavonoids of 14 Linum taxa from three sections were examined by 2-dimentional paper and thin-layer chromatography. The extracted flavonoids belong to three main groups. The kind as well as number of flavonoids varied between the taxa. PCA-biplot confirmed that some of the studied taxa had unique flavonoids, which were useful in their identification. Some types of flavonoids such as kaempferol and quercetin were general and had no chemotaxonomic values. While other types of flavonoids had restricted distribution and were useful in identification of the studied taxa. The species classification in the UPGMA tree and also PCA and PCO plots did not confirm the traditional grouping of the species in sections. Apparently, that traditional infrageneric classification of the genus must be changed.
