Mention the Sahara Desert to anyone and they'll describe a barren wasteland with no life and no hope. While it is something of a barren wasteland, there are enough Sahara Desert plants that it can also be described as teaming with life. It's not a matter of enough water, or too much heat during the day and cold at night, but a matter of how life has found a way to adapt to and survive in this unusual environment.
Many people don't realize that after the last ice age the Sahara Desert was quite a different place than it is today. Sahara Desert plants were far more abundant, and of the type that thrived on much more water. Today many of the plant species there not only can make it with little water, they do better when the water is scarce as it is in a desert. It's just like animals that adapt to cold conditions. it seems harsh where they live, but put them into a warmer climate and they won't last for very long.
Typical Sahara Desert plants include shrubs and grasses. Grasses in particular can get by with not much water because they tend to spread over such a large area and therefore can taken in enough moisture to survive. These desert grasses aren't like the lush green lawns found in suburban yards, but they survive in an environment where not much can make it. the same can be said of the trees. Don't expect leafy shade trees like the ones in the country pictures.
One reason leaves are a huge disadvantage for Sahara Desert plants is the amount of surface area they have. Hot, dry conditions of a desert cause rapid evaporation. Plants would soon die if their moisture flew off into the atmosphere. a large surface, such as a leaf, promotes evaporation. Needles and spines, however, don't have as much surface area and thus evaporation is less rapid. for a similar reason cactus have thick trunks, so the water within is further from the surface where evaporation takes place. It's all a matter of holding onto moisture during the long dry periods.
It's not just dry heat Sahara Desert plants must withstand, it's also a soil rich in salts. Thus many of the plants in the desert are halphytes, which are plants that can tolerate high salt concentrations.
The Sahara Desert, as do hot deserts in general, presents a number of challenges for plants that grow there. But Sahara Desert plants grow and thrive because life always finds a way