Anthemissect.Hiorthia (Asteraceae) on Kriti Island, Greece: high ploidy levels and a new species

A morphological and karyological investigation of the Anthemissect.Hiorthia representatives of Kriti (Greece) revealed that three different species are found on the island, all endemic, and each characterised by a different ploidy level based on the haploid series of x = 9. Anthemisabrotanifolia, the species with the widest distribution, is tetraploid with 2n = 4x = 36. A.samariensis, a local endemic of the Lefka Ori, was found being decaploid, with 2n = 10x = 90, the highest number ever recorded in Anthemis. The recently discovered population on Mt. Kedros (south-central Kriti) is morphologically distinct from all the Anthemis entities growing on Kriti; it also differs from the variable and widespread A.cretica group. It is here described as a new species, A.pasiphaes Goula & Constantinidis. It is a hexaploid, with 2n = 6x = 54. All chromosome numbers are reported for the first time. Polyploidy might have acted as a reproductive barrier among these perennial species, complementing isolation by spatial distance and evolutionary divergence. Further, it might have contributed adaptation advantages to these three predominately mountain species.