Comparative Anatomy of Some Verbascum Taxa (Scrophulariaceae) in Southeastern Anatolia and Distinguishing Characteristics of These Taxa

The Verbascum L. genus (Scrophulariaceae) is global in distribution. Turkey is the genus's hub of genetic diversity, and it contains the greatest number of species within it worldwide. The genus Verbascum has significant morphological diversity, making species classification difficult. The anatomy of the roots, stems and leaves of seven Verbascum taxa (Verbascum agrimoniifolium subsp. agrimoniifolium, V. orientale subsp. orientale (group A), V. laetum (group C), V. geminiflorum (group I), V. andrusii, V. kotschyi (group K), V. lasianthum (group L)) found in the Southeastern Anatolia Region (Diyarbakır, Mardin, and Şanlıurfa Province) of Turkey formed the basis of this study. Cross-section of root, stem and leaf samples from seven different Verbascum taxa were cut by hand and then examined under a light microscope. The xylem components play an important role in taxonomic root parts. The pith region is a large region in stem sections, and the upper part of the epidermis cells is surrounded by a separate indented cuticle layer. The main vein of the leaves is represented by lateral bundles. The presence of idioblasts (V. laetum and V. geminiflorum) has observed in the leaf. In this study, the importance of various characteristics in Verbascum taxa limitation was investigated. In order to support morphological features in taxonomic classification and assist in genus systematics, some characters typically associated with anatomical patterns (such as the presence of idioblasts in the leaf) can be applied.