Characterized by vast plains, escarpments, plateaux and wadis, the central desert divides Northern Oman from Southern Oman. Many of the plant species in the central desert are endemic to Oman and occur nowhere else in the world. Generally, vegetation is sparse with occasional Prosopis cinerea and Acacia tortiliswoodlands restricted to depressions (haylahs).Plants of note include: Ochradenusharsusiticus, Rhusgallagheri, Nannorrhopsritchieana and Hyoscyamusgallagher.