Abstract

The high morphological diversity among species of the genus Verbascum causes problems in the delimitation of the species. Therefore, there is a difficulty in offering a natural and well organized classification for the species of the genus. This research was based on the leaf anatomy of 20 species of Verbascum growing in north and middle of Iraq. Leaf samples from 20 species of Verbascum were cleared and stained, was then to examine by light microscopy. Idioblasts occurred both adaxially and abaxially and have a thin primary wall and were empty at maturity, the increase of idioblasts leads to irregular the mesophyll thus the shape of blade in cross section and can divided the species in to irregular mesophyll and regular mesophyll. All species of Verbascum have crystals appeared very clear in the epidermis.we recorded stomatal type and found all  the species under study  have anomocytic type of stomata and characterized by the fact uniformly amphistomatic (stomata both abaxial and adaxial) and the stomatal apparatus lacked accessory (subsidiary) cells also. The shape of the guard cell on the upper and lower surface are reniform in all species under study, But there are differences in the ordinary cells surrounding the stomata and the cell shaped where are appeared as two types, the first type is the ordinary cells straight walls and ribbed and the cell shapes are rectangular to oval and the second type is the ordinary cells are undulate and irregular walls or wavy edge and the cell shape are rectangular to polygonal.Study showed that the trichomes are normally divided into two groups depending on that in Verbascum species under study to glandular trichomes and unglandular trichomes and the last one also can divided in to two types of trichomes, the dendroid trichomes and asteroid trichomes, clear from result of study the species V. agrimoniifolium is smooth from upper surface and the trichomes appear just in the lower surface.