These are found in South Africa & as far as temperature they can survive to limited levels of -5° centigrade (23° fahrenheit). Watering should be done when the leaves start to shrivel. The flowers are shown in autumn with the colours being anywhere from white to peach.
Sadly I do not know the species name, however they are within the Lithops group.
A good friend of mine sent me a picture that he thought was funny. After looking at it, I agreed.
Adromischus ~ Astrophytum ~ Cephalocereus ~ Cereus ~ Cyanotis ~ Echinopsis ~ Epiphyllum ~ Espostoa ~ Ferocactus ~ Frithia ~ Gymnocalycium ~ Haworthia ~ Hildewintera ~ Lophocereus ~ Mammillaria ~ Notocactus ~ Opuntia ~ Pilosocereus ~ Rebutia ~ Schlumbergera ~ Sedum ~ Sempervivum ~ Stenocereus ~ Sulcorebutia ~ Tephrocactus ~ Turbinicarpus ~ Weberbauerocereus