Calyptridium quadripetalum, synonym Cistanthe quadripetala, is a species of flowering plant in the family Montiaceae.

[citation needed] It is endemic to the North Coast Ranges of California, where it is an uncommon member of the serpentine soils flora on the slopes.

It is a small annual plant spreading or erect stems each a few centimeters long.

There is a basal rosette of small, thick leaves and a few along the stems.

The inflorescence is a dense cluster of sepals and four white to pink round petals.