The genus Castilleja is a highly specialized member of the subfamily Rhinanthoideae of the family Scrophulariaceae. The wildflower enthusiast recognizes many of the species as Indian paintbrushes. The name alludes to the resemblance of the inflorescence of closely appressed flowers and bracts to a freshly dipped paint brush. The Castilleja viscidula group is a relatively natural assemblage, consisting of nine species and centering in the western United States. The species are easily recognized by their wavy-margined leaves and glandular pubescence. This treatment of the Castilleja viscidula group includes keys, descriptions, black and white illustrations, and distribution maps.