Issue Information

COVER ILLUSTRATION: In a genus known for morphological and taxonomic challenges, the vibrant floral bracts of Castilleja have long fascinated botanists. Despite the group's high diversity in the western U.S., Castilleja coccinea, the scarlet paintbrush, is one of the few eastern species and displays striking flower color polymorphism. While scarlet is predominant, a yellow morph appears in some populations, primarily in the Midwest region. In “Selection maintains floral color polymorphism in the scarlet paintbrush Castilleja coccinea (Orobanchaceae)” in this Special Issue (“Paradigm Shifts in Flower Color”), Fetterly et al. explore abiotic and biotic factors shaping this polymorphism. They identify habitat differences as potential drivers of color divergence, while floral trait variation suggests pollinators and environment act together to maintain distinct morphs. (Image credit: Jeremie Fant.)