A savanna will generally lie between a tropical rain forest and a desert. The amount of water they receive allows them to support tall grasses but only a few trees. The savanna's rain comes mostly during the "wet season." Because of this, the plants living therein have become highly specialized to survive the long season of drought. As a result, savannas, while simple in structure, are also highly complex ecosystems.
Most savannas are flat or have only gentle swells. These are called "savanna woodlands." Like most savannas, they receive the majority of their rainfall during a brief "wet" season. Due to the long dry season, plants living in the savanna woodlands have become highly specialized. While plants in the rain forest, for example, survive with far-ranging surface roots to take advantage of the forest floor's available nutrients, the plants of the savanna woodlands have all grown deep root systems, to reach water reserves. Many trees of the savanna woodlands grow deep "tap roots" early in their growth cycle, as this is an important priority if the plants are to live.
The "stone country" is a second type of savanna that has far more varied terrain. It primarily consists of plateaus and the rocky escarpments on their edges. Often in these areas, steep inclines and high winds mean there is little room for soil to accumulate. Without soil to soak up rain, these areas only hold water for a short time. Yet even here, tough grasses are able to take root. Like the savanna woodlands, these areas play host to highly specialized plants.
A third landform in the savanna is the flood plain. As the name implies, flood plains are full of water during the wet season --- and are almost entirely devoid of it during the dry season. During the wet season, flood plains teem with plant and animal life. Many birds and reptiles use these areas as breeding grounds, heading off to wetter climes during the rest of the year. The flood plains are also sometimes called the "black soil plains," as silt is left behind by the receding water yearly.