Résumé
This study aims at identifying the nature of natural vegetation at the middle and high altitudes regions in the area under study .The field study has shown the vegetation affluence of this region, of which 116 plant species, belonging to 86 genera and distributed among 45 families, have been collected .It has also illustrated the prevalence of the communities of herbs, shrubs and dwarf hushes. Moreover, the study has demonstrated that there is a plant variation between Lawder and Mukayras due to the increase in their altitudes. It is worth mentioning that some plant species, such as Anisotes trisulcus, have been extinct [disappeared] in the areas with an altitude of 1500 rns. The region under study is characterized by unique different ecological factors and circumstances: weather and geotopography such as cliffs, slopes and the prevailing rock structures, in addition to the weakness of soil profile with scarce and intermittent rainfall. Besides, it has been noticed that there are some succulents that have been prevailed such as Adenium obesum, Euuphorbia spp. and Caralluma spp