Introducing Flora, Life From, and Geographical Distribution of Plants in Ashtian Urban Watershed (Markazi Province)

The urban watershed is located in the North of Ashtian city which is a cold mountainous area. The altitude of the region ranges from 2090 to 3071 meters. Urban watershed region of Ashtian covers an area of 5542 hectares and is located in the northeast of Arak city. The annual precipitation of the region is 283 millimeters and the mean annual temperature is 9.6 ºC. The aim of this research was to identify the plant species, introduce flora, and determine life forms and geographical distribution of species in the watershed. For this purpose, plant samples were collected from the watershed during the growing season of 2015 and 2016. The biological spectrum of the watershed was plotted by means of life form results. The position of the watershed within Iran’s phytogeography classification was studied based on geographical distribution data and available resources. In this study, 262 belonging to 43 families and 139 genera were collected and identified. The following families had the highest number of species: Asteraceae (with 38 species), Papilionaceae (with 36 species), Gramineae (with 22 species), Lamiaceae (with 20 species), Apiaceae (with 18 species), and Liliaceae (with 17 species). Hemicryptophytes, with 124 species (47.3%), were the most frequent life form in the region. Investigating the geographical distribution of species, it was observed that 199 species (76%) belong to Irano-Turanian region.