The Atlantic Forest is the most species rich vegetation in Brazil and holds several phytophysiognomies, including the vegetation on inselbergs, which is a very stressful xeric environment that selects for very specialized biota. Cololobus is an endemic genus from Atlantic Forest inselbergs of eastern Brazil, and Cololobus ruschianus is a new species based on morphological evidence, differing from other species of the genus by its morphological traits in petioles, subinvolucral bracts, and outer involucral bracts. Cololobus ruschianus occurs in Santa Teresa, Espírito Santo State, Brazil and would likely be considered Critically Endangered (CR), based on the criteria of the IUCN red list.