A Study of the Floristic Composition, Life Form, and Chorology of Plants in Three Areas of Abhar County (South East of Zanjan Province)

Abstract Abhar County, with 3362 km2 area is located in 90km southeast of Zanjan and 230 km west of Tehran. The average altitude of this region is 1540 m.a.s.l., the mean annual precipitation is 323.5 mm and the average annual temperature is 12.51 °C. Three regions in three different locations of Abhar County were selected to represent the general pattern of vegetation diversity in this County. In order to identify the plant species and introduce the floristic composition, life forms and chorology of plants, samples were collected during the growing seasons in 2015 to 2016. The total of 310 plant species belonging to 220 genera and 53 plant families were determined. The largest families were Asteraceae (29 genera and 44 species), Fabaceae (14 genera and 28 species), Poaceae (19 genera and 25 species), Lamiaceae (12 genera and 25 species), Apiaceae (19 genera and 24 species), Brassicaceae (19 genera and 21 species), Caryophyllaceae (12 genera and 17 species), Boraginaceae (13 genera and 15 species), Rosaceae (7 genera and 12 species), Ranunculaceae (7 genera and 9 species), Amaranthaceae (5 genera and 6 species) and Rubiaceae (6 genera and 6 species). The largest genera were Astragalus (8 species), Salvia (7 species), Centaurea (6 species), Silene (5 species), Achillea, Bromus, and Stachys (4 species). Regarding the chorological point of view, the largest proportion of the flora belonged to the Irano-Turanian elements (54.2%). Hemicryptophytes were the dominant life form and consisted of 50% followed by therophytes (29.7%), geophytes (9.3%), phanerophytes (5.8%) and chamaephytes (5.2%). The current research findings revealed the floristic richness of Abhar County.