The genus Hymenocrater (Lamiaceae, Mentheae) comprises 11 species in Flora Iranica of which nine species are mostly distributed in Iran. Among Iranian species, five are found in the Razavi, North and South Khorasan provinces. Eighty morphological characters were measured in 44 herbarium specimens belonging to: H. calycinus, H. bituminosus, H. platystegius and H. elegans. The Kruskal-Wallis Test was implemented to evaluate which characters significantly differentiate the species. Thus, forty-two morphological characters were used in subsequent analyses. Taxonomic relationships were investigated using the Principal Component Analysis (PCA). H. bituminosus and H. platystegius were separated in two distinct groups. There was no sharp distinction between the two other species, H. calycinus and H. elegans. Canonical discriminant analysis (CDA) was also applied to find the best discriminating traits among the species.