Biosystematics of Sisyrinchium section Bermudiana (Iridaceae) of the Rocky Mountains

Prior to this study thirteen taxa ofSisyrinchium sectionBermudiana were recognized as occurring in the Rocky Mountains. Morphological intrapopulational variation and hybridization with polyploidy has led to a general lack of discrete phenetic discontinuities among the species, resulting in differing taxonomic treatments. A biosystematic study utilizing morphology, cytology, analysis of breeding systems, and hybridization was undertaken to resolve the taxonomy of Rocky Mountain populations ofSisyrinchium. The following taxa are considered to be valid species of the Rocky Mountains:S. septentrionale Bicknell, a tetraploid (n=16), the octoploids (n=32)S. idahoense Bicknell andS. radicatum Bicknell, and the duodecaploid (n=48).S. montanum Greene. In addition, a previously undescribed, octoploid species,S. pallidum (with close affinities toS. idahoense) was discovered in north-central Colorado and southeastern Wyoming.