Cool cacti
Cacti are succulent perennial flowering plants belonging to the family Cactaceae, of the order Caryophyllales. Botanists estimate that there are about 1,650 cacti species, grouped into 130 genera.  Although a few species inhabit tropical or subtropical areas, most live in and are well adapted to dry regions. Cacti generally have thick herbaceous or woody chlorophyll-containing stems. In most species, leaves are either absent or greatly reduced, minimising the amount of surface area from which water can be lost, and the stem has taken over the photosynthetic functions of the plant, making them most suitable for dry conditions.
Cacti vary greatly in size and general appearance. A few cacti develop small plantlets at ground level that, as offsets, reproduce the species vegetatively. Tissues of cacti are broadly compatible so that terminal portions of one species may be grafted on top of another, making them a delight for amateur gardeners.  The National Cactus and Succulent Society of India Organises the cacti show regularly, wherein over 200 varieties of cacti in bloom are showcased. Chandigarh has some of the world’s best varieties of cacti.
Flowering and pollination in cacti is as mysterious as that of their adaptability to dry conditions. Cacti flowers are colourful and usually solitary. This genus in the family Cactaceae has about 20 species. The genus is known for its large, usually fragrant, night-blooming white flowers, which are among the largest in the cactus family. However, the blooming period is only for a few hours, when they have to attract pollinators.
The queen-of- the-night (S grandiflorus), the popular night-blooming cereus, is often grown indoors, although it does not occur in India. Bhrahma Kamala is an important, sacred cacti flower, dedicated to Lord Bhramha. This species also blooms only for a few hours in the early hours of the day.
In recent times, commercial cultivation of cacti for export as well as the domestic market has become an important part of the floriculture business in many parts of India like Kalimpong in Darjeeling, Kolkata, Hyderabad, Nagpur, Pune, Chennai, Jhansi, Gwalior, Bhopal, Panchkula and Bhuvaneshwar.
From the annual sale of these plants, a multi-billion dollar business has been established the world over. However, in Karnataka, the commercial growing of cacti is the need of the hour.