Indian paint brush, any plant of the genus Castilleja (family Scrophulariaceae), which contains about 200 species of partially or wholly parasitic plants that derive nourishment from the roots of other plants. For this reason the plants are seldom cultivated successfully in the flower garden. The small, tubular flowers are irregular (two-lipped). They are surrounded by upper leaves that are brightly coloured either throughout or at the ends only, giving the plant an appearance of having been dipped in a pot of red, orange, yellow, pink, or white paint.