Plant Fact File: The Cactus

The cactus has a scientific name of ‘Cactaceae’. The largest cactus species in the world is the ‘Pachycereus Pringlei’ which can reach about 19 meters in height. The smallest cactus in the world is the ‘Blossfeldia Liliputina’ which only reaches a few centimetres in height. The cactus spends much of its time staying dormant; as soon as it begins to rain the plant will relish the opportunity by growing, flowering and storing as much water as possible.


The cactus has many adaptations these include:

1) Thick waxy cuticle (coating) across the cactus – A cactus has a thick waxy coating to significantly reduce the water loss.

2) Thick, folded stem – A cactus has a thick, folded stem so, that the cactus can store as much water as possible in the stem during short periods of damp weather.

3) Spines instead of leaves – Cactuses have spines instead of leaves to reduce water loss and to protect it from desert herbivores.

4) A stem that is capable of carrying out photosynthesis – As the cactus’s leaves have become spines the cactus has evolved, to allow its stem to be able to carry out the process of photosynthesis.

5) Long roots – The roots of a cactus is thick and long means that the cactus can send out its root deep into the ground and spread out to maximise the chance of obtaining some water in the dry and tough desert soil.

6) CH4 – Unlike other plants the cactus can open its stomata (small pores on the stem or left) during the night in order to store as much carbon dioxide and remove as much oxygen as possible in order to enable photosynthesis to take place. When the stomata are open the plant will lose vast amounts of water over a short space of time, to combat this, the cactus has evolved to open its stomata during the night and keep them closed during the day, and this helps to dramatically reduce water loss. Other plants are CH3 which means they can only open their stomata during the day while the are photosynthesising.

Facts about the cactus include:

1) There are over 2000 species of cacti.

2) Cactuses are native to the Americas (from the southern tip of South America to Western Canada). However, there is an exception to this rule the ‘Rhipsalis Baccifera’ which can be found in many parts of Africa, small pockets of India and Sri Lanka. This plant believed to have came from the Western Hemisphere as a result of birds eating the seeds from this cactus and then expelling them once they arrived to Africa and India.

3) There are around 1750 different species of cacti. Depending on the species a cactus’ spines can be very fragile.

4) A large saguaro cactus which has a scientific name of ‘Camegiea Gigantea’ is capable of storing a staggering 50 litres of water in a single rainfall.

5) Also a large saguaro cactus will only lose a mere glass of water in a single day, while an apple tree in the UK can loss a whole bath full of water in the same amount of time.

6) It is very possible for 90% of the mass of a cactus is water.

Some cactus species are vitally important for wildlife for example the cactus wren only makes its nests inside or on a cactus. Cactuses are pollinated by butterflies, moths, bees and hummingbirds. An interesting fact is the hummingbird is capable of beating its wings up to 90 times every second. The cactus is a relatively useful plant as it is a very hardy and adaptable plant is can be grown for commercial use so it can be eaten and given to livestock (once the spines are removed). They can also be used to make medicine.

Thank you for reading.


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