A plant that is adapted to live in conditions in which there is either a scarcity of water in the soil, or the atmosphere is dry enough to provoke excessive transpiration, or both. Xerophytes have special structural (xeromorphic) and functional modifications, including swollen water-storing stems or leaves (see succulent) and specialized leaves that may be hairy, rolled, or reduced to spines or have a thick cuticle to lower the rate of transpiration. Another common adaptation of xerophytes is crassulacean acid metabolism, which enables the uptake of carbon dioxide at night, when temperatures are lowest, and closure of leaf pores (stomata) during the daytime to conserve water Examples of xerophytes are desert cacti and many species growing on sand dunes and exposed moorlands. Some halophytes have xeromorphic features. Compare mesophyte; hydrophyte.