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.

Pollen morphology of 19 taxa of the genus Plantago was studied and documented in detail using scanning electron microscopy (SEM). The pollen grains are small to medium-sized (P = 18.7‒44.0 µm, E = 13.7‒34.2 µm), prolate-spheroidal to prolate (P/E = 1.05‒1.54 µm) in shape and pantoporate. Based on SEM observations of tectum ornamentation, three groups of taxa can be distinguished: the Ovata group with scabrate tectum, the Major group with coarsely verrucate tectum and the Lanceolata group with finely verrucate tectum. Multivariate analyses indicate that, the pollen morphology is not taxonomically significant at the subgenus and section levels, but it is useful for delimitation at the infraspecific level, and also for understanding the morphological diversity at the species level.