Cousinia : morphology, taxonomy, distribution and phytogeographical implications

Cousinia (Compositae) with over 400 species in SW Asia has its maximum concentration in the Flora Iranica area. Overall it has a remarkably limited distributional range compared with other genera of similar size. On the basis of the significant distribution patterns of Cousinia , it is argued that the highland part of the Flora Iranica area should phytogeographically be re-designated as the Irano-Turkestanian region, including the Central Asian mountain province of Soviet Central Asia. It is also proposed that the essentially lowland Turanian (Aralo-Caspian) area should be excluded from the Irano-Turanian region.