Özet:
The floristics characteristics of Köse mountain are given and the vascular plant species growing there have been documented. Köse mountain is situated northeast of Sivas and close to the northern parts of the Anatolian Diagonal. It is in the transitional zone of the Euro-Siberian and Irano-Turanian phytogeographical regions. In the vegetarian period, a total of 3500 plant specimens were collected from the are between 1984 and 1987. At the end of the study, 1137 vascular plant species were identified, belonging to 85 families and 419 genera. Of these, 165 species are endemic to Turkey. The phytogeographic elementss are represented in the study area as follows: Irano-Turanian 305, Euro-Siberian 163, Mediterranian 55. One species is new for the Flora of Turkey.