Glottiphyllum is a genus of about 57 species of succulent subtropical plants of the family Aizoaceae. It is closely related to the Gibbaeum and Faucaria genera. The name comes from ancient Greek glottis “tongue” and phyllon “leaf”. The species are native to South Africa, specifically to the Cape Province and the Karoo desert. They grow in rocks and soils incorporating slate, sandstone and quartz. Rainfall in their native areas is between 125 and 500 mm, most of which falls in March and November. Glottiphyllum plants have thick, soft leaves arranged in pairs that are low to the ground and often graze the soil surface. They also have rhizomes. They sport yellow flowers with narrow petals in autumn and winter. The flowers are sometimes fragrant and around 5 cm in diameter. The species readily interbreed, making hybridization easy.

Glottiphyllum regium, synonymously known as Glottiphyllum compressum and commonly known as Tongue-leaved Mesemb in English and Tongblaarvygie or Skilpadkos in Afrikaans, is a rare South African endemic succulent mesemb found in the Western Cape province. Glottiphyllum regium is a hardy, clump-forming succulent that produces masses of showy, large, yellow flowers from mid-winter until early summer. Glottiphyllum regium is a clump-forming succulent and can attain a height of 13 cm and a width of 15 cm. It has a semi-fibrous, shallow root system typical of succulents. The roots are not destructive and plants can be planted right next to structures. Glottiphyllum regium is assessed as endangered. It occurs over a relatively small area and at five locations, the populations are decreasing due to the habitat being degraded by grazing, trampling and soil erosion due to ostrich farming.