Hamideh Javadi - Ph. D. student, Research Institute of Forests & Rangelands, P. O. Box ۱۳۱۸۵-۱۱۶. Tehran, Iran
Seyed Mohsen Hesamzadeh Hejazi - Assistant Professor/Department of Biotechnology. Research Institute of Forests & Rangelands, P. O. Box ۱۳۱۸۵-۱۱۶, Tehran, Iran
Majnun Shikhbaba Babayev - Profeaaor/Department of Genetic, Baku State University, Azerbaijan

Thymus (Thyme) is one of the most important medicinal plants which is highly variable within and between the species. This variation is in morphology, components of essential oil and number of chromosomes. So, in this study, two Thymus (Thyme) species including Th. trautvetteri Klokov & Desj-Shost and Th. fedtschenkoi Ronniger which are distributed in south of Azerbaijan country, were investigated. Examined species belong to the sect. Serpyllum and subsection Kotschyani. Some species of this section are taxonomically very difficult and show the widest chromosomal variation. In this research, the somatic chromosome numbers of examined species were counted at least in five mitotic cells. The basic chromosome number was x=۱۵ with two ploidy levels. Th. trautvetteri with ۲n=۴x=۶۰ and Th. fedtschenkoi with ۲n=۲x=۳۰ were tetraploid and diploid respectively. Chromosome counts for these species are new reports.

Thymus, chromosome number, Ploidy