Tamarix L. play important role in preventing deforestation in Iran. Tamarix species exhibit wide range of morphological variation therefore, the species delimitation become difficult. This is further complicated due to similarity of morphological characters in closely related species and the occurrence of inter-specific hybridization. The present study was performed to identify Tamarix species and their potential hybrids in Semnan Province of Iran. We used ITS and ISSR and 42 morphological characters for our investigation. Molecular phylogeny of the studied species and their relationship was not in agreement with the species tree of morphological characters and with taxonomic treatment of the genus. HGT tree of ITS and morphological data obtained revealed the occurrence of inter-specific hybridization or introgression between Tamarix species.
Helichrysum oocephalum is a medicinal plant of the genus Helichrysum that have limited distribution in Iran. Local geographical populations may differ in their genetic content and form different gene pools. Therefore, we carried out population genetic investigation and morphological studies in five geographical populations of Helichrysum oocephalum by using ISSR molecular markers. AMOVA produced the significant genetic differences. The mean Nm value revealed some degree of gene flow among Helichrysum oocephalum 8. Molecular and morphological analysis indicated that we have 2 groups in the studied populations. The present findings may be of use in the conservation of this medicinal plant in Iran.