The Pacific Coast Irises are a group of eleven closely related plant species. That many species pairs form fertile hybrids in the wild makes them an ideal system for the study of speciation. This is a proposal to study three of the naturally occurring hybrid zones, analyzing at least eight characters per hybrid zone, to see (1) if the character's frequency distributions coincide, and (2) if these distributions are concordant along transects within and between hybrid zones. To complement these studies of patterns of variation, the following potential barriers to gene flow will be examined: habitat association, flowering time, dispersal rate and the fitness of hybrids. The hybrid zone studies will be placed in the context of a phylogeny of the entire group of irises, relying on cladistic analysis of morphological and molecular (cpDNA, rDNA, allozymes) characters.
