The Succulent room
Plants living in extremely dry environments are often succulent, i.e., they store water in their leaves, stems, or roots. Many develop spines or lack leaves entirely. Cacti (Cactaceae) from America, the Spurge family (Euphorbiaceae) from Africa, and genera of the Didiereaceae from Madagascar have similar life forms despite not being closely related. The Living Stones Lithops from Southern Africa are, when not in flower, hardly distinguishable from the pebbles among which they grow.