A friend, who collects cacti, told me recently that someone asked him why people keep thorns at home. The general impression is that cactus is synonymous with thorns. The cactus belongs to the family of succulents. The word ‘succulent’ is derived from the Latin word ‘succus’ meaning juice. The word ‘cactus’ is derived from the Greek word ‘kaktos’ which literally means a prickly plant. The main characteristic of a succulent plant is the fleshy stem in which moisture is stored. So, in brief, plants with thorns are cactus and those with fleshy stems are succulents, though there are exceptions.

The fascination of cacti lies in their different shapes and colours. Some plants change their colour when exposed to the sun like Crassula erasula—a green plant which turns red when placed in the sun. It is also known by the nickname ‘campfire’. Unlike other plants in which too much of sun is dangerous, in the case of some cacti, it makes them even prettier. One generally feels that cacti are gaunt and ugly. However, there are many plants which prove otherwise. Haworthis casperi is a green rose-like plant with transparent leaves. Plants belonging to the Ariocarpus and Lithops species are very difficult to identify in their natural surroundings because they look like stones. The Kalanchae have silvery white-felted leaves with brown markings at the edges. Another unusual shape is Sedus mergianum.

The fact that these plants have beautiful flowers and tasty berries is unknown to many. Stapelia variegata has star-shaped yellow flowers with a purple centre. That such strange-looking plants that are different from flowering plants should have such beautiful flowers is indeed a miracle of nature. Some plants flower only at night—like the Star of Bethlehem which is at its best at midnight and closes its petals before sunrise.

In some cases, the flowers are followed by berries, which are edible. There is a mistaken notion among people that these berries are poisonous.  The Mammillarias have red fruits which taste like strawberries. The pears of the Opuntia are delicious.

The thorn one is familiar with was probably the leaf of the plant thousands of years ago. The plant has gradually changed its form to suit climatic conditions. The main function of the thorns is to protect the plant from animals and also to deflect the sun’s rays so that the maximum amount of moisture can be retained. If one were to observe these thorns closely one would notice the symmetrical patterns they form. It seems as though one has measured and placed them at appropriate distances.

Cacti can be propagated through seeds, grafting and leaf-cutting. In the case of leaf-cutting, some succulents drop the petals and a new plant will grow from the end of the petal. The red-turban plants of Gymnecalycium optimarubra do not contain chlorophyll so they cannot exist on their own and have to be grafted on to another plant.

Other than decorative purposes, cacti have various other uses. In South Africa, Euphorbias are used as fodder for cattle.

It is called ‘breakragg’ which means the strength of an ox. When the animals are tired after their work, they are fed Euphorbias to revitalise them. Sometimes, in the desert, these cacti have helped people to quench their thirst. People dig up the cacti and drink the water from the roots. In Mexico, the Agave produces an alcoholic drink called ‘pulque.’ Many cacti are used for medicinal purposes.

A certain species of Fechea is used as a vegetable. In Arizona (U. S. A.) the Papago Indians grind the seeds of Carnegiea gigantea and use it as flour. The wooden part of the cactus Cereus is used to make walking sticks, fences and furniture. The fibre is used for making baskets and mats. The thorns are used for making fish hooks and pins.

In recent years, the popularity of the cacti has grown and more and more people are taking up cacti collection as a hobby. The Mumbai-based Cactus and Succulent Society is doing a lot to foster interest in cacti. They have about 4,000 members all over India and abroad.