Helianthemum greenei is a rare species of flowering plant in the rock-rose family known by the common name island rush-rose. It is endemic to the Channel Islands of California, where it grows in the chaparral of the rocky seaside slopes. It is present on three of the eight islands, where it has historically been threatened by feral herbivores such as the Santa Cruz sheep and is making a gradual recovery. It is a federally listed threatened species. Today this plant is found on Santa Cruz, Santa Catalina, and Santa Rosa Islands; it has not been recorded on San Miguel Island in several decades.