A cactus is a plant that grows where the soil is dry and rocky, most usually in the desert. A cactus doesn’t have leaves like other plants do. There are 1,500 to 1,800 species of cacti.
Cacti come in all shapes and sizes from round and short through to thin and tall. The smallest grow just a few centimeters high and about 1 cm (0.4 in) across. The tallest cactus can reach heights close to 20m (66ft) and up to 1 meter thick.
The cactus manages to collect its water using its quite large root system. Small thin roots grow near the surface of the soil and collect as much rainwater as quickly as possible during the few times it rains. Cacti can also have a single long thick root called a taproot which grows much deeper to reach underground water supplies when the top soil is dry.
Some cactus can be eaten and some grow fruit. The dragon fruit is now widely grown in Asia. In some countries like India they will use to cut this in herbal medicine. The cactus can also be used for fodder for animals once the spines have been removed.
DIFFERENT TYPE OF CACTUS