Molecular data confirm morphological variability in the widespread foliose lichen Canoparmelia carolinana (Parmeliaceae)

Canoparmelia caroliniana is among the most common macrolichens in southeastern North America, occurring on the bark of trees in habitats from urban centers to pristine wilderness. Canoparmelia amabilis was distinguished from C. caroliniana on the basis of differences in the color of the lower surface and morphology of the isidia. Recent fieldwork revealed previously overlooked morphologically variability within C. caroliniana, prompting a revision based on morphology, ecology, and analyses of nrITS sequence data. These data do not support the distinction between C. amabilis and C. caroliniana, and indicate that C. amabilis should be placed in synonymy with C. caroliniana. Analyses of nrITS sequence data confirmed the monophyly of C. caroliniana (including C. amabilis) as well as that of C. cryptochlorophaea and C. texana. A lectotype is selected for Canoparmelia amabilis because the holotype is presumed to be lost.