ABSTRACT
Israel is largely worried about its deserts because they constitute half, or more, of the country’s area. Israel‘s deserts are located at the meeting place of three world deserts, namely: the Sahara, Central Asian and the Sudano-Sindian. Rainfall is the most decisive factor in the life and death of plants, and in Israel’s deserts there are quite a number of places which are altogether plantess because of insufficient rain. The decrease in the yearly amount of rainfall from north to south is much more abrupt in the desert than in the sown area. The antiquity of the desert flora is shown by the occurrence of plants with highly elaborated morphological and ecological features and devices for survival which required geological ages for their evolution. Plants are ecological entities endowed with environmental requirements. Quite a number of deserts are ecologically analogous or even homologous, in regard to moisture, and yet they are completely different from one another in their biota.
