Dionysia (Primulaceae): the Cushion Primroses

Dionysia comprises 64 species of aromatic dwarf shrubs growing in crevices of steep or often overhanging rocks in semi-arid areas. Most species form cushions, and are covered in violet or yellow flowers in spring. They are restricted to the South-central part of the Irano-Turanian floristic region, ± corresponding to the Flora Iranica area. Several species have been used since antiquity for medicine and incense. Until the late 19th century, the drug Hamámá (Dionysia diapensiifolia) was markete