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Vegetation is one of the most important parts of natural ecosystems that in addition to express of the growth conditions, it also shows the influence of ecological factors on the environmental condition. Investigations of plant diversity of a country are necessary for studyingthe ecosystem, pasture, plant gene bank, agriculture and medicine. On the one hand, identification of plant species of different regions provide feasibility of doing of next studies in the different fields of biological science. In this research the flora of Tang sorkh region in the Kohgiloyeh county from Kohgiloyeh-va boyerahmad province has been investigated. The area of mentioned region is 5000 hectares and it is located in 30 kilometers from the east of Yasuj. Maximum altitude of the area was between 1800-2800 m. Our research has started by collecting the essential information of the region. The plants of region have been collected and prepared for studying. several floras were used for identification the specimens and they are preserved in Alzahra University herbarium (ALUH). This investigation showed that in the Tang sorkh region, there are 46 families, 145genera, 172 species that include 6/97% of phanerophytes, 5/23% chamephyts, 43/60%hemicryptophytes, 13/95% geophytes, 28/48% therophytes. Analyses shows that most of species of region belongs to the Iran-o-Turanian region which contanins 5/69% of region’s flora. 23 species are endemic to Iran, 20 of which are rare species, 30 species are medicinal plant, 22 of which are poison. Totaly about 172 species has identified. 20 species are recorded for the first time from this province.