Serpentine is a very unique dark green rock. Thanks to its dark colour it is very heating, and therefore, the temperature of the rocks is usually very high when it is insolated. Serpentine is a hard rock, which effloresces very slowly. Therefore also soil is very shallow and extensively becomes drying. The soil is also very nutrient poor for plant growth. Moreover, serpentine soil contains considerable quantities of heavy metals, especially magnesium. Only a small number of plant species (so-called serpentinophytes) is able to survive in these extreme conditions. Some species can occur strictly only on serpentine substrate and nowhere else (so-called obligate serpentinophytes), while other species can occur also at other than serpentine substrate (so-called facultative serpentinophytes). The facultative serpentinophytes however usually look differently when growing on serpentine substrate than on "normal" soil substrate. They tend to be smaller in size and more hairy on serpentine. This deviation is called the "serpentinomorphosis".