Amin Zeraatkar - Research Division of Natural Resources, Chaharmahal and Bakhtiari Agricultural and Natural Resources Research and Education Center (AREEO), Shahrekord, Iran
Magnus Lidén - Systematic Biology, Institute of Organismal Biology, EBC, Uppsala university, Norbyvägen ۱۸D, SE-۷۵۲۳۶ Uppsala, Sweden
Tooraj Mokhtarpour - Research Division of Natural Resources, Chaharmahal and Bakhtiari Agricultural and Natural Resources Research and Education Center (AREEO), Shahrekord, Iran
Hamzeh Ali Shirmardi - Research Division of Natural Resources, Chaharmahal and Bakhtiari Agricultural and Natural Resources Research and Education Center (AREEO), Shahrekord, Iran

Botanical exploration in ۲۰۲۲ in the province of Chaharmahal and Bakhtiari, resulted in the collection of Dionysia bachtiarica, a narrow endemic species first collected in ۱۹۰۲ and described in ۱۹۰۵. This species has not been seen since ۱۹۰۳. Some morphological features were incompletely recorded, absent, or untrustworthy in earlier descriptions, due to limited herbarium material. In this study, new morphological data are provided based on analysis of live flowering and fruiting material, illustrated with photographs of the plant and its habitat, as well as line drawings. A full description of the species, its ecology, and phenology, as well as a key to all purple-flowered species in the Zagros Mountains, are provided. The possible relations of this enigmatic species are discussed. Due to its extremely limited known area of occurrence and a small number of individuals, it is considered to be Critically Endangered.

Chaharmahal and Bakhtiari, narrow endemic, Sabz Kuh, subnival–nival species, Threatened Species, Zagros