Manually constructed keys for identification of plants leave much to be desired. Keys to the Asteraceae of Egypt are no exception and depend largely on floral minutiae while vegetative morphology is a much richer source of characters suitable for key construction. Inspection of some 3000 specimens showed that the most obvious feature of the plants is the presence or absence of spines on leaves, leaf axils, stem internodes, margins of stem wings and phyllaries. This feature was selected to divide species of this family into two main groups: spiny and spineless. Nomenclature of all taxa was updated and those with names reduced to synonyms of others were eliminated. This article deals only with the 65 species belonging to 20 genera of the first group. A total of 51 characters describing variation in spine distribution and other characters of vegetative morphology were recorded for each of the 65 spiny species and the key-generating program DELTA was applied to the data matrix. The result is a much improved automated key, a detailed description of every species in terms of the entire set of 51 characters, and the same description but in terms of the serial numbers assigned to these characters and their states.