Dionysia is a genus consisting of small cushion-forming or rosette-forming plants in the Middle East, with the majority of the species growing in Iran or Afghanistan. They are alpines and grow on the shady side of cliffs or under overhangs where they are shielded from the sun. The rosette-forming species strongly resemble members of Primula subgenus Sphondylia, which share the same distribution and habitat. The hypothesis of a close relationship between these two groups has been strongly supported in recent molecular studies. In addition, it has been shown that the position of these two groups in relation to the rest of Primula is not basal. The present study uses sequences from four different DNA regions (both nuclear and chloroplast) as well as morphological data to construct an internal phylogeny of Dionysia. The evolution of morphological traits are discussed in the light of the new systematic position of the genus, which has changed what can be considered primitive character states.

Key words: Dionysia, phylogeny, Primula, Primulaceae