What Does Cactus Family Comprises Of?
Cactus is a member of the plant family Cactaceae which comprises about 175 genera with over 2000 species of unusual plants with beautiful flowers, which are found mainly in North America, with a few species in South America, Africa and Sri Lanka. Mexico has the greatest number and variety of species. Although a few cactus species inhabit tropical or subtropical areas, most live in and are well adapted to dry regions.
Cacti grow in dry places such as deserts, and store water in their strange, thick stems. They have no real leaves, but bear spines which help to protect them from animals. Cactus lifespan typically ranges from 10 to 200 years, depending on the species. Cacti growing outdoors in ideal conditions tend to live longer than those cultivated as houseplants. However, with good care many indoor cactuses can live for many decades.
One of the most unusual cacti-and now, sadly, a threatened species-is the giant cactus, a saguaro. This plant can live for over 200 years and stands like an enormous branched candlestick in deserts of south-west United States of America. There was even one which lived in Arizona until the mid 90s which was thought to be about 300 years old. This amazing cactus, which lived in Saguaro National Park eventually died of a bacterial infection, which older cacti are vulnerable to, particularly if they have been weakened by injury.
A saguaro is able to absorb and store considerable amounts of rainwater, visibly expanding in the process, while slowly using the stored water as needed. This characteristic enables the saguaro to survive during periods of drought. The saguaro is a columnar cactus that grows notable branches, usually referred to as arms. As many as 49 arms may grow on one plant. They grow from 3–16 m (9.8–52.5 ft) tall, and up to 75 cm (30 in) in diameter. They are slow growing and are the largest cactus in the United States.
The enormous popularity of cacti among gardeners and plant collectors is surpassed only by that of roses and orchids. Their appeal extends far beyond their native habitat; there are legions of devotees in the eastern United States, Europe, and Japan. The desire to possess these strange yet beautiful plants supports hundreds of specialty nurseries; the largest shops grow and sell millions of plants annually. Cacti are one of the reasons tourists visit the American southwest.
Most people think they know a cactus when they see one, but they are often mistaken. All cacti are succulents, but not all succulents are cacti. Agaves, ocotillos, aloes, and the succulent euphorbias (such as African milk trees) are among the swollen or spiny plants often mistaken for cacti. However, the term cactus refers to a particular family of plants defined by a distinctive flower pattern. To be a cactus, the plant must produce flowers with the following characteristics: many tepals (combined sepals and petals) that intergrade with each other; many stamens (usually hundreds), and numerous stigma lobes (rarely only three). If a plant lacks such a flower, it cannot be a cactus.