XVI International Botanical Congess

The atypical covering tissue appears in roots of Gentiana species as a result of radial divisions of exodermal and endodermal cells. In some species it is a secondary one and develops by means of cell divisions in the multilayered pericycle and even in the secondary phloem. In last case its development is regularly repeated. This earlier unknown secondary tissue was discovered also in the roots of Gentiana lutea that have a typical periderm at the late stages of development. The evolution of covering tissues system in Gentiana roots is characterized by the consequently lost of periderm and finally of the described atypical tissue in the process of the ontogenetical abbreviation.