PHYTOSOCIOLOGICAL BEHAVIOR OF THYMELAEA-HIRSUTA (L) ENDL IN EGYPT

The present study identifies 18 vegetation groups associated with the distribution of Thymelaea hirsuta (an evergreen desert shrub) in six t ypes of habitat (coastal ridge overlain by calcareous dunes, inland ri dges, saline depressions, non-saline depressions, inland plateau with skeletal soils, and inland siliceous deposits) in the western Mediterr anean region of Egypt. Five of these groups are dominated or codominat ed with T. hirsuta (2 on the ridges, 2 in the depressions and 1 in the inland plateau). The effective complexes of soil variables in the phy tosociological behaviour of this plant are calcareous sedimentation an d fertility on the ridges, salinity in the depressions, and siliceous sedimentation and salinity on the inland plateau. Although it tolerate s wide environmental gradients, it does not perform best at their extr emes.