Very dwarf and succulent plants, with their fleshy leaves arranged in dense rosettes, and mostly with curious but seldom conspicuous flowers, abounding in mountainous regions, and very hardy. The greater number of these grow quite as freely as the common Houseleek in any arid soil, and in any position where the vegetation is not taller than themselves, such as on bare sandy banks, gravelly heaps, etc. There are about fifty hardy kinds in cultivation in the gardens in this country.