Circumnutation in the growth of Chara rhizoids

The chromosome numbers of 24 species of Achillea L. were determined, among them 4 for the first time (A. chamaemelifolia, A. sulphurea, A. teretifolia, A. vermicularis). A tetraploid form of A. lingulata was found for the first time. The occurrence of di- and tetraploid forms of A. crithmifolia and A. setacea is confirmed as are tetraploid forms of A. asiatica and A. sibirica. Attention is drawn to 7 species of Achillea L. occurring in two forms, di- and tetraploid, and the significance of this fact is discussed