A glasshouse for plants from climates with low, irregular rainfall but also for plants of dry locations such as cliffs or tree branches. This house is allowed to follow ambient temperatures except for low-level heating in times of frost. Water is given about three times weekly in summer, reducing to zero between October and March.

The cacti and some spurges, Euphorbia spp., store water in swollen stems - so are called 'stem succulents'. Leaves are insignificant or non-existent, so reducing water loss by evaporation. By contrast desert plants like agaves and aloes store water in fleshy leaves which minimise water loss by thick waxy cuticles - these are 'leaf succulents'.

As well as cacti, this house contains a collection of 'living stones', carrion flowers, and century plants. Some plants of economic importance, e.g. sisal, Aloe vera, can also be found here.