In this study, the morphological and anatomical characteristics of Onosma frutescens Lam. and Onosma inexspectata Teppner were investigated. O. inexspectata is an endemic species. Both examined species have secondary root structure, and cortex is multilayered and composed of parenchymatical cells. While, xylem is composed of sclerenchymatic cells and tracheary elements in roots of O. frutescens, xylem is composed of tracheal elements in roots of O. inexspectata. Glandular and eglandular trichomes are present on the epidermis of stem of both species. Parenchyma cells are 28.12 ± 7.55 × 24.90 ± 5.42 min stem of O. frutescens. Parenchyma cells are 37.35 ± 8.66 × 17.09 ± 3.44 m in stem of O. inexspectata. Stomata are anisocytic and anomocytic. Vascular bundles are surrounded by a parenchymatic sheat in both species. Key words: Boraginaceae, Onosma, morphology, anatomy, Turkey.