The Northern Cape has a semi-arid to arid climate with a low rainfall and extreme temperatures from as low as -8oC in winter to 41oC in summer. So how do plants manage to survive under these conditions?
Many of the desert plants are dwarf-like and have small leaves which lose less water than large leaves. Examples are the small Karoo shrubs, many of which can also drop their leaves during the hot months and grow new ones after it rains or when it gets cooler.
Some plants store water in their leaves. This helps them to survive long periods without rain. Well-known examples are aloes, such as the Kokerboom Aloe dichotoma. Others store water in their stems. Many Euphorbias do this and, in addition, some species have a waxy layer that coats the stems to prevent water loss.
Vingerpol, Euphorbia species, is a stem succulent which contains a poisonous milky latex
Stone plants are adapted in a number of ways. They are very small, have only a few, very succulent leaves, and are half buried beneath the soil to escape the heat and reduce moisture loss. They have the same colour and markings as the pebbles or soil around them, and are therefore camouflaged and well hidden from herbivores (plant-eating animals). They often grow between light-coloured pebbles on which dew condenses at night when they cool, and the moisture droplets are then quickly absorbed by the shallow roots of these plants.
A stone plant, Lithops species
Another way plants escape the heat is to grow in the shade of another plant or a rock. Many of the Stapeliads, which are small stem succulents with large, attractive flowers, grow inside shrubs where they are sheltered from direct sunlight and animals.
Light-coloured leaves reflect sunlight which helps to keep the plant cool. Antimima lawsonii, a dwarf, compact shrub, has very small, light-coloured leaves which do just that. This plant also grows between whitish pebbles which further improves the local micro-climate.
Antimima lawsonii, a dwarf succulent shrub.