New or Rare Data on Chromosome Numbers in Several Taxa of the Genus Artemisia (Asteraceae) in Poland

Chromosome counts in 16 populations of five Artemisia species from Poland are presented in this paper. Those of A. annua (2n=18) and A. dracunculus (2n=90) are reported for the first time in Polish populations. The decaploid level (2n=90) is described for the first time in non-cultivated populations of A. dracunculus, and several cases of aneusomaty (intraindividual aneuploid variations in chromosome number: 2n=87, 88 and 89) have been detected in this species. In addition to the already known diploid number (2n=18), the tetraploid level (2n=36) has been detected in A. absinthium. The same two numbers have been recorded in A. abrotanum, which represents the first tetraploid count in populations of this taxon occurring outside botanical gardens. Finally, the chromosome number of Artemisia campestris subsp. sericea (tetraploid, 2n=36) is reported for the first time. The relevance of polyploidy for the evolution of the genus and other cytotaxonomic or cytobiogeographical aspects are briefly discussed.