Comparative leaf, stem and root anatomies of taxa Marrubium bourgaei and Marrubium heterodon (Lamiaceae)

Marrubium genus is represented by 19 taxa in Flora of Turkey (19 species, 3 subspecies). 11 out of 22 taxa are endemic for Turkey and rate of endemism is 52%. Anatomical, histological and cytological features of the leaf, stem and root in Marrubium bourgaei and M. heterodon taxa of genus Marrubium L. from Lamiaceae family were studied and taxonomic significances were identified. The leaves were amphistomatic and hypostomatic. Stomata were amaryllis type and anomocytic as indicated by neighbouring cells. The leaves of the examined Marrubium species were bifacial (dorsiventral) and a high number of prismatic crystals were observed in the leaf mesophyll tissue. The stems were angular and stomata were observed in local areas of epidermis. The underneath of stem epidermis were a few layers of collenchyma cells. In leaf cross sections, protective tissue was comprised of periderm and a nucleus at the center consisting of tracheids