The vegetation-environment relationship in the inland saltmarshes of Siwa and Dakhla, two geographically distant oases of the Western Desert of Egypt, are described. Two data sets (25 species x 68 relevés for Siwa Oasis, 29 species x 89 relevés for Dakhla Oasis) were analysed by multivariate procedures. Two-way indicator species analysis (TWINSPAN) was used to classify the plani communities ofthe study areas, whereas detrended correspondence analysis (DCA) and detrended canonical correspondence analysis (DCCA) were used to examine the relationship between the vegetation and selected edaphic factors (soil reaction, electric conductivity, calcium carbonate, organic matter, moisture conteni and fine fractions. Twelve halophytic plani communities linked to two main habitats (wet-moist and dry-mesic) were identified. In the two oases the most common communities are those of Alhagi graecorum, Tamarix nilotica, Cressa eretica, Juncus rigidus and Phragmites australis. Communities of Cyperus laevigatus, Suaeda aegyptiaca, Suaeda vermiculata, Typha domingensis and
Aeluropus lagopoides are recorded from Dakhla Oasis; Cladium mariscus and Arthrocnemum macrostachyum communities are recorded from Siwa Oasis. The most important edaphic factors affecting distribution and structure of these piant communities are salinity, moisture content and fine fractions; CaCO3 content seems to be more effective in the Dakhla Oasis.
