Abstract Onobrychis Miller (Hedysareae, Fabaceae), with about 150 species in the world and more than 77 species in Iran, in 2 subgenera and 9 sections, includes annual or perennial herbs or shrubs. The genus is mainly distributed in northern temperate regions; however, centres of its genetic diversity are in the Eastern Mediterranean area and South-West Asia. Some pod and seed characters in the genus such as existing and durability of sepal, fruit and seed size, shape, colour, dorsal and ventral ornamentation have important role in seed dispersion and taxonomy. Studies of these characters can revealed the relationship between taxa and used for identification and numerical taxonomy of the species. Twenty three pod and seed quantitative and qualitative characters of nine collected Onobrychis taxa from different part of Markazi Province, Iran were studied using ruler, caliper and a zoom binocular light microscope. Data were coded and analysed by principal component analysis (PCA) test using the SPSS, and then cluster analysis was performed. Results showed morphological studies of pods and seeds of Iranian members of genus Onobrychis showed some characters may support the identification of its species and varieties. Finally a key based on the Onobrychis Miller fruit and seed characters was prepared.
