Aim and background. Cornelian cherry (Cornus mas L.) belongs to the family Cornaceae. It is a tall deciduous shrub or small tree of 5 to 8 m high. This plant is popular in Southern Europe and Asia. Fruits of these species are not only consumed fresh but also used to produce jam, jelly, stewed fruit, marmalade, syrup and several types of soft drinks. It is also used for medicinal purposes due to properties of stalk and fruits. The leaves and seed of this species is used in pharmaceuticals. The tree is also valuable for ornamentation as an evergreen broadleaf plant. Despite the widespread use of cornelian cherry, a few studies on this plant have been conducted in Iran.

Materials and Methods. In this research 6 populations of Cornus mas belongs to Cornus genus that collected from 3 locations of Iran, studied using root apex meristem, number and dimensions of chromosomes in the mitosis division measured, and determined karyotypic formula for any population.

Results.The number of genome was 9 and kind of chromosome was metacentric, sub-metacentric and sub-telocentric. The most and lowest mean of chromosome length belongs to C2 population (47.7 micron) and C3 population (3.50 micron) respectively. The populations were compared using stebbins method based on karyotype. C2 and C3 lied in 1A class and other populations in 2A class, so C2 and C3 populations were symmetrical than others. Karyotypic formula of C1, C2, C4, C5 and C3 and C6 was determined as 10m+8sm and 6m+12m respectively.

Conclusion. Cytological samples showed minor differences in this sample compared to other samples, for example, a satellite is in samples C5 pairs of chromosome No. 4.