Crocanthemum 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.

Its leafy stem is mostly green, with new growth and inflorescences at the top often appearing purple in color.

The inflorescence is generally a panicle, producing many buds which open into golden yellow flowers one to two centimeters wide.