NUTLET AND FLOWER MORPHOLOGICAL AND MICROMORPHOLOGICAL STUDIES ON ONOSMA L. (BORAGINACEAE) IN IRAN

The morphology and micromorphology of flower and nutlet in 29 Iranian Onosma species were examinated comparatively using SEM method in order to evaluate and clarify their taxonomic values and specific emphasis was on their role in classification. Our study highlights the importance of the floral and nutlet characters in relation to identification of most of the studied species based on the PCoA and cluster analysis. Besides, Palynological, morphological and molecular studies confirmed our results. Although there are some taxa which cannot be determined solely using the mentioned characters, but these characters accompanied with other important characters are useful tools in distinguishing many taxa and solving some complexities in Onosma. Moreover if molecular evidence (chloroplast and nuclear sequences) confirm our results, the divergence of Onosma orientalis and Onosma rostellata from the genus Onosma is expexcted, then these taxa may be transferred to different genera. On the other hand, combinations of these characters along with morphological and molecular evidence provide a perfect view for taxonomy and comphrensive taxonomical revision of Onosma.