Artemisia norvegica subs. saxatilis
Variation within Artemisia norvegica in North America is not well understood and, for that reason, this treatment represents a conservative taxonomy with only one subspecies for the flora area. Subspecies saxatilis differs from typical A. norvegica primarily by its larger heads. European plants have involucres less than 10 mm in diameter. Chromosome number may be used to justify separation of taxa either at the level of subspecies or species. If separated as distinct species, then A. arctica is the name for North American plants. The diploid A. arctica (2n = 18) and tetraploid A. comata (2n = 36) are treated as separate species by R. Elven et al. (pers. comm.).