Weird and wonderful members of the plant kingdom - Living Stones

Commonly known as 'living stones', the genus of plants called Lithops is one of the most popular among collectors of cacti and succulents. They are found almost exclusively in habitats classed as desert. To be a true desert, an area must receive on average less than 10 inches of rain a year, but most Lithops live in places lucky to see a fifth of that amount. These plants live on the edge of survival. They are native to southern Africa, and have been found growing wild in only three countries - Namibia, Botswana, and South Africa.

They're called living stones because in their natural habitat they have evolved to mimic the stones and pebbles which often litter the ground where they grow. As stones can be different colours, so are Lithops. The hues and patterns produced by these plants are extremely wide and there is an obvious reason for their behaviour. There are many small mammals which share the same arid habitat as Lithops - and which would be only too glad to bite into the juicy leaf of a succulent and quench their thirst. Not only does resembling a stone act as a form of camouflage, but the dense skin of the top of a Lithops leaf is a deterrent to most insects.

Although commonly called living stones, Lithops have been known by other names. Local Afrikaaners called them beeskloutjies - or 'cattle hoof,' and skaappootjies - 'sheep hoof,' and they have also been called 'belly plants', presumably because you have to crawl on your belly in order to find them! In Namibia they are sometimes known as ombuma yombwa or 'dog testicles'.

Living Stone photograph by superfantastic, used under a creative commons attribution licence