I am posting from London, UK. I have this fleshy plant with a distinctive tuber at the base, which is clearly used to toughing-out extreme drought. It is slightly thorny, with distinctive red, almost crimson, new foliage and branches.
It has a very interesting habit: at sundown, the leaves fold into each other from the outside inwards. The result is a single, thick, leaf profile.
This habit may well be to reduce water loss by evaporation at night - a wild guess here.
But can anyone i.d it, please? Even a genus would be good.
http://www.thetripflare.org/xerophyte/
Many thanks in advance