Xanthoparmelia rubromedulla is a species of saxicolous (rock-dwelling), foliose lichen in the family Parmeliaceae. Found in South Africa, it was formally described as a new species in 1986 by the American lichenologist Mason Hale. The type specimen was collected from Waaihoek Peak (Worcester Division, Cape Province) at an elevation of , where it was found growing on a sandy rock face above a stream. The lichen thallus, which is loosely attached to its rock , is light yellowish green and measures in diameter. It contains salazinic acid, usnic acid, and skyrin.