Lithops is a genus of succulent plants in the ice plant family, Aizoaceae. Members of the genus are native to southern Africa. They avoid being eaten by blending in with surrounding rocks and are often known as pebble plants or living stones.
Individual Lithops plants consist of one or more pairs of bulbous, almost fused leaves opposite to each other and hardly any stem. The slit between the leaves contains the meristem and produces flowers and new leaves. The leaves of Lithops are mostly buried below the surface of the soil, with a partially or completely translucent top surface known as a leaf window which allows light to enter the interior of the leaves for photosynthesis. The name is derived from the Ancient Greek words λίθος (lithos), meaning "stone," and ὄψ (ops), meaning "face," referring to the stone-like appearance of the plants.