The present book deals with the floristic diversity and vegetation composition of the functional groups in the southern part of the Egyptian Eastern Desert were investigated through four transects (3 crossing the Eastern Desert and one along the Red Sea). These transects were (1) Qena-Safaga road, (2) Idfu-Marsa Alam road, (3) Aswan-Kharit-Gimal and (4) Red Sea Coastal Plain. A total of 94 plant species belonging to 33 families were recorded. Shrubs represented the largest functional group, while perennial herbs represented the smallest one. The application of cluster analysis technique has provided usefully tool in classifying stands into many vegetation groups coinciding with ecological variations. The soil-vegetation relationships were assessed by both DCA and CCA. Studying the functional groups (trees, shrubs, perennial herbs and annual herbs) responses to soil variables showed spatial changes that may affect functional groups. (CCA) used to elucidate the responses of the studied FGs to their environment. The species diversity indices of the FGs showed significant correlations with the soil gradients. There was a correlation between the coarse sand and trees diversity.