Sanicula mariversa is a rare species of flowering plant in the carrot family known by the common name Waianae Range black-snakeroot. It is endemic to Hawaii, where it is known only from the Waianae Mountains on the island of Oahu. It is threatened by the degradation of its habitat. It is a federally listed endangered species of the United States. As of 2006 there were 18 mature individuals and 170 immature plants remaining.