Is Ptarmica independent genus or attached to Achillea ptarmica, tribe Anthemideae, Asteraceae?

Abstract

Ptarmica impatiens L.(diploid; 2n=18), P. ledebouri (Heimerl.) Serg.(tetraploid; 2n=36) and P. salicifolia (Bess.) Serg. (tetraploid; 2n=36) taxonomically close relatives with and are sometimes placed in the genus Achillea grown commonly in the well northern colder region. The karyotypic comparison showed Ptarmica is somewhat different from Achillea although they were placed in the tribe Anthemideae, the family Asteraceae. Ptarmica should be independent genus separated from Achillea and more meritorious in an ornamental and horticultural purposes.