The flora of Yemen is a mixture of the tropical African, Sudanian plant geographical region and the '''Saharo-Arabian region'''. The Sudanian element—characterized by relatively high rainfall—dominates the western mountains and parts of the highland plains. The Saharo-Arabian element dominates in the coastal plains, eastern mountain, and the eastern and northern desert plains. A high percentage of Yemen plants belong to tropical African plants of Sudanian regions. Among the Sudanian element species, the following may be mentioned: ''Ficus'' spp., ''Acacia mellifera, Grewia villosa, Commiphora'' spp., ''Rosa abyssinica'', ''Cadaba farinosa'' and others. Among the Saharo-Arabian species, these may be mentioned: ''Panicum turgidum, Aerva javanica, Zygophyllum simplex, Fagonia indica, Salsola'' spp., ''Acacia tortilis, A. hamulos, A. ehrenbergiana, Phoenix dactylifera, Hyphaene thebaica, Capparis decidua, Salvadora persica, Balanites aegyptiaca'', and many others. Many of the Saharo-Arabian species are endemic to the extensive sandy coastal plain (the Tihamah). The characteristic genera of the Irano-Turanian in the eastern and northern east of the country are: ''Calligonum'' spp., ''Cymbopogon jwarancusa'', and ''Tamarix'' spp. and of the Mediterranean regions are: ''Teucrium, Lavandula, Juniperus, Brassica'', and ''Diplotaxis'' spp.