Wadi Quena, unique in its north-south orientation among other wadies of the eastern desert of Egypt constitutes a vast catchment system of sporadic rains over the Red Sea mountains. The present study concerns a part of this catchment area, including some eastwest tributaries pouring flood waters into the lower part of the main trunk of the wadi. Due to local physiographic factors, these tributaries harbour two communities newly recognized in this desert. These are: community of Salsola haryosma-Tamarix aphylla and community of Cilrullus colocynlhis-Cleome droserifolia. Elements of the alliance Zygophyllaeion coccini, previously identified in this series of investigations, are well represented in the area under consideration.