Cousinia: morphology, taxonomy, distribution and phytogeographical implications

Abstract

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.