Salvia macrosiphon Boiss., is a complex species of the genus Salvia L. (Lamiaceae), which widely distributed in different regions of Iran. There are discussions about infraspecific diversity in this species, and some varieties have been definite for it in different flora. However, no infraspecific taxon was listed for this species in Flora Iranica and Flora of Iran. In the current study, floral morphological characteristics were examined in 11 Iranian populations of S. macrosiphon to detect how these characteristics differed among the populations. In total, 10 floral quantitative characteristics were examined with 10 replications per characteristic. Data was analyzed using SPSS and PAST software. Results revealed that the average amounts of the studied characteristics varied among the populations. The ANOVA test explored a significant difference (P≤0.01) persisted among all the examined traits. In this regard, the largest and smallest calyx lengths belonged to Mashhad and Sabzevar populations, respectively. The widest and narrowest calyces were observed in the Takestan and Ghadamgah populations, respectively. The Ghadamgah population had the largest length of corolla, while its shortest amount was detected in the Sabzevar population. The widest corolla was recorded for the Aghdareh population, and the narrowest corolla belonged to the Ghadamgah population. The largest and shortest calyx teeth belonged to the Semnan and Sabzevar populations, respectively. Moreover, some significant positive/negative correlations existed among the studied features. According to UPGMA tree, the evaluated populations were classified into three distinct clusters, then, each cluster was subdivided into some groups. However, the clustering pattern for some populations was not in accordance with the geographical distance, which was resulted from the difference in genetic structure or speciation. According to these findings, it was concluded that high morphological diversity existed among the examined populations, which agreed with the results of previous molecular and phytochemical studies for this species.
