SynopsisThe distribution and ecological characteristics of the thorn-cushion formations (Tragacanthic vegetation) in the western part of SW Asia are discussed. The typical structure of this formation is illustrated by 2 examples from the mountains of the Antilebanon. These show a clear zonation in relation to the growth form. This, and the available micro-climatological data, show that thorn-cushions reach their ecological optimum on windswept slopes and hill tops. This growth form is obviously an adaptation for sites exposed to strong winds. Taxa with this growth form have a competitive advantage in such habitats.