The Cactus, a much loved staple from the desert appearing on indoor student home desks all across the world, is a family of succulents (and occasionally epiphytes) native to most places which are prone to drought. Cacti are usually found with thick fleshy stems which are always green. Many species of Cacti have lost their true leaves in favour of spines, which minimises the surface area from which precious moisture can evaporate. Cacti, being geared towards water retention, only undergo transpiration (an exchange of oxygen and carbon dioxide) at night, when the cooler temperatures reduce the likelihood of water evaporating. The cause of death for most home cacti is too much water.