PHYLOGENETIC STUDIES OF ANEMONE STYLOSA
A collection of the allotetraploid Anemone stylosa Nelson from Heliotrope Mts., Gunnison, Utah, was successfully crossed with A. multifida Poir. (tetraploid) and the diploids A. riparia Fern., A. virginiana L., A. silvestris L., and A. pavonina Lam. The karyotype of A. stylosa resembles that of A. multifida except for modifications of chromosome VII in the “large set” and chromosome IV in the “small set”. Meiotic analysis in A. stylosa × A. multifida hybrids indicates that these modifications are due to a chromosome interchange and that this is the only detectable chromosome rearrangement between the two species.Analysis of the crosses with the diploids corroborates these conclusions and suggests that the donor of the “large-chromosome” set of A. stylosa had the A. riparia karyotype rather than the A. virginiana one. A. stylosa may have originated as a variant of A. multifida in which an interchange became established homozygously.