Peduncle anatomy was investigated in 20 species of Onobrychis Miller sect. Heliobrychis Bunge from Iran by light microscopy. Ten quantitative and qualitative characters were studied in the peduncle cross sections. Results showed that qualitative characters represent considerable variations within the section, some of which such as outline shape of the peduncle cross section, density of papillae on hair surface, and position of cavities in peduncles are taxonomically important characters to differ annual species from perennials in the section. Four groups were distinguished within the perennial species according to peduncle anatomical characters. In addition, a key is provided for the taxa based on these characters.

Peduncle anatomy was investigated in 20 species of Onobrychis Miller sect. Heliobrychis Bunge from Iran by light microscopy. Ten quantitative and qualitative characters were studied in the peduncle cross sections. Results showed that qualitative characters represent considerable variations within the section, some of which such as outline shape of the peduncle cross section, density of papillae on hair surface, and position of cavities in peduncles are taxonomically important characters to differ annual species from perennials in the section. Four groups were distinguished within the perennial species according to peduncle anatomical characters. In addition, a key is provided for the taxa based on these characters.