Succulent plants are plants that store water in their enlarged fleshy leaves, stems, or roots. The enlargement in succulents is usually due to the greater amount of the parenchyma tissue, such as in the aloe vera plant.
Although all plants store water, succulent plants are especially adapted to store water for extended periods. This allows them to survive in arid environments, where they receive only small amounts of competition from other plants and less herbivory. By day, their habitat is rather hot. However, the habitat is cooler at night allowing the succulents to respire. Morning dewfall helps the plants to survive, as the long hairs that cover a large part of their surfac are able to absorb dew.
Many have a waxy coating on their stems and leaves, helping them to hold on to moisture. Having a large internal volume for storage but minimum surface area is also very important to prevent water loss. CAM photosynthesis is also a commonly found water conservation feature in many of them. Succulence is a feature due to convergent evolution and is not necessarily an indication of a genetic relationship. There are succulents in many unrelated families (more or less 50, some sources note only 28). But, for some families, most members are succulent; for example the Cactaceae, Agavaceae, Aizoaceae, and Crassulaceae.
