Roya Karamian - Department of Biology, Herbarium division, Bu-Ali-Sina University, P.O. Box ۶۵۱۷۵/۴۱۶۱, Hamedan, Iran
Ali Moradi Behjou - Department of Biology, Herbarium division, Bu-Ali-Sina University, P.O. Box ۶۵۱۷۵/۴۱۶۱, Hamedan, Iran
Morteza Atri - Department of Biology, Herbarium division, Bu-Ali-Sina University, P.O. Box ۶۵۱۷۵/۴۱۶۱, Hamedan, Iran
Massoud Ranjbar - Department of Biology, Herbarium division, Bu-Ali-Sina University, P.O. Box ۶۵۱۷۵/۴۱۶۱, Hamedan, Iran

Onobrychis melanotricha (Fabaceae) is an endemic perennial herb in Iran and has two varieties. For investigating on infraspecific variation within O. melanotricha, ۱۴ releves were performed in its different habitats in Hamedan province according to the Braun-Blanquet method and samples were gathered using phytosociological approach. Results showed that each variety occupies one of main mountainous and sub-mountainous habitats. They correlate together by a continuous gradient in morphological characters. In addition, different patterns of variation and related effective factors are discussed. O. melanotricha var. ecbatanaica is described and illustrated from Hamedan Province as a new variety. It differs from the type variety by having the large simple leaves.

clinal variation, Endemic, FCA, Hamedan, Iran, O. melanotricha, PCA, Phytosociology, UPGMA