Abstract— The circumscription of Brodiaea coronaria has remained in a state of flux over the past 200 yr. That species name historically was applied to a morphologically-diverse assemblage of populations ranging from southern California to coastal southern British
Columbia. Recent floristic works recognized two subspecies, B. coronaria subsp. coronaria, which ranges from northern California to British Columbia, and B. coronaria subsp. rosea (currently = B. rosea), considered to be a serpentine endemic of northwestern
California. A morphometric analysis was done to better refine the circumscription of both taxa. Ten floral characters and the length of the longest pedicel in the inflorescence of 10‐50 were measured in plants from 63 populations of B. coronaria and five populations of B.
rosea. Principal components analysis and cluster analysis were employed to determine whether discrete population groups could be recognized, and a discriminant analysis was done to further test these groups and to identify diagnostic characters. The results support a revised circumscription
of B. coronaria, with many former populations of B. coronaria transferred to B. rosea. The analysis supports recognition of B. rosea at species rank, emended to include many non-serpentine populations. A new subspecies, B. rosea subsp. vallicola,
is proposed for morphologically distinct populations that occur along the eastern edge of California's Central Valley. Despite this revision, B. coronaria remains a widely ranging and highly variable species, and further genetic and molecular data are needed to assess whether morphologically-cryptic
polyphyletic lineages may be present.