THE TAXONOMIC SIGNIFICANCE OF LEAF ANATOMY IN THE GENUS ONOSMA L. (BORAGINACEAE) IN IRAN

The leaf anatomy of representative species of Onosma L. from Iran have shown that the type of hairs are characteristic features in distingushing species and group of species within the genus. In internal structure of lamina two distinct groups are recognized within Onosma; sections Protonosma M. Pop. and Podonosma (Boiss.) Gruck with dorsiventral mesophyll and sect. Onosma mainly isobilateral. Several anatomical characters are associated with xeromorphy. Leaf anatomy supports the division of the genus Onosma L. into 3 sections.