each recognized species has noticeable phenotypic and habitat differences, yet similarities between their phenotypes and habitats can be drawn. these similarities are partially a result of their similar phylogenies. many of the species are closely related, some a result of interbreeding, as in the most recent discovery of the abbeville red iris, "iris nelsonii". the five louisiana irises are often categorized as "the reds" or "the blues" according to their corolla color. "the blues", species "iris brevicaulis", "iris hexagona", and "iris giganticaerulea", typically have blue-purple corollas, with rare white forms. "the reds", species "iris fulva" and "iris nelsonii", typically have red-orange corollas, with rare yellow forms. between 1920s and 1930s, dr. john k. small extensively studied irises in both florida and louisiana and named over 80 new species, including "iris savannarum", iris kimballiae, iris albispiritus and iris rivularis. subsequent research has determined that only "iris savannarum" is a true species and the others are synonyms of it.