Facts about Cactus for Kids
Gathered by: Will
- The word “cactus” derives, through Latin, from the Ancient Greek κάκτος (kaktos), a name originally used for a spiny plant whose identity is not certain.
- Cacti are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north—except for Rhipsalis baccifera, which also grows in Africa and Sri Lanka.
- Most species of cacti have lost true leaves, retaining only spines, which are highly modified leaves.
- As well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade.
- Cactus stems also store water, and are often ribbed or fluted, which allows them to expand and contract easily.
- Like other succulent plants, most cacti employ a special mechanism called “crassulacean acid metabolism” (CAM) as part of photosynthesis.
- At least superficially, plants of the genus Pereskia resemble other trees and shrubs growing around them.
- Their areoles identify them as cacti, and in spite of their appearance, they, too, have many adaptations for water conservation.
- Most cacti—opuntias and cactoids—specialize in surviving in hot and dry environments, but the first ancestors of modern cacti were already adapted to periods of intermittent drought.
- They can provide some shade, which lowers the temperature of the surface of the cactus, also reducing water loss.
- The majority of cacti are stem succulents, plants in which the stem is the main organ used to store water.
- These may be several times the length of the above-ground body in the case of species such as Copiapoa atacamensis, which grows in one of the driest places in the world, the Atacama Desert in northern Chile.
- Later botanists, such as Philip Miller in 1754, divided cacti into several genera, which, in 1789, Antoine Laurent de Jussieu placed in his newly created family Cactaceae.
- If Pereskia clade A is a good model of these early cacti, then, although they would have appeared superficially similar to other trees growing nearby, they had already evolved strategies to conserve water.
- Except for a relatively recent spread of Rhipsalis baccifera to parts of the Old World, cacti are plants of South America and mainly southern regions of North America.
- Cacti are often grown in greenhouses, particularly in regions unsuited to the cultivation of cacti outdoors, such the northern parts of Europe and North America.
- When cacti are grown in containers, recommendations as to how this should be achieved vary greatly; Miles Anderson says that if asked to describe a perfect growing medium, “ten growers would give 20 different answers”.