Cactus: All About This Amazing Sharp Plant

by Australian Flowers

Curious about Cactus? These spiky succulents are pretty fascinating plants! Native to arid regions, cacti are adapted to survive in hot, dry climates. If you have a cactus (or are thinking about getting one), it’s essential to care for it properly.

Read more to learn about cacti, from their anatomy to their exciting facts!

Morphology of Cactus


This plant is a member of the plant family Cactaceae, within the order of Caryophyllales. They are typically succulent plants with thick photosynthetic stems and leaves modified as spines. Most cacti feature extensive root systems that help the plant capture rainwater and soil nutrients.

Cacti come in a wide range of shapes and sizes. Most miniature of this plant is only a few millimetres in diameter, while the largest can grow up to 20 meters tall! In terms of leaves, cacti can have either none at all or large, fleshy leaves that are adapted for water storage.

Growth Habitat

Cacti are found in various habitats, from hot and dry desert regions to high mountain slopes and tropical rainforests. Some cacti even grow in the sea! The vast majority of species are native to America, with a few found in Europe, Africa and Asia.

Most cacti are succulents, which means they have thick fleshy stems or leaves that store water. This cactus is adapted to living in dry climates and can survive long periods without water. Cacti come in all shapes and sizes. The tallest cactus ever recorded was 19.2 metres (63 feet) tall! Most miniature cactus is only a few millimetres (less than 0.2 inches) in diameter.


The stem is the part of the plant that typically grows above ground. It is mainly composed of water and stores nutrients for the plant. Generally, green in colour and has a spongy texture. The stem is covered in tiny, sharp spines that protect the plant from predators, and is also home to the plant’s flowers and fruits.

The stem is an integral part of the plant and serves several purposes, it also stores water and nutrients for the plant, helps the plant to stand upright and produces flowers and fruits.


The areoles of the plant are the small, knob-like structures found on the surface. These areoles can be used to identify cacti, as they are unique to this plant family. Areoles may be covered in spines, hair, or wool and typically contain small flowers.


Cacti leaves are often spines, which are modified leaves that grow spiral. They are adapted to reduce water loss in hot, dry climates. The plant has a waxy coating on its leaves that helps to reflect light and heat, preventing the plant from getting too hot, and it also has a thick layer of skin that helps to protect it from the sun’s rays.


The spine is a sharp, needle-like outgrowth of the cactus plant. Most cacti have crests, and they serve several purposes. They help protect from predators, and they also help to shade from the sun. The spines also help to give their unique shape.


There are two different types of roots. The first type is the taproot, and the second type is the fibrous root system.

  • The taproot is the main root that grows straight down into the soil. This type of root is typically found in plants that grow in dry conditions. The taproot helps the cactus to anchor itself in the soil and to absorb water from deep in the ground.
  • The fibrous root system comprises many small roots that grow close to the soil’s surface. This type of root system is typically found in plants that grow in moist conditions. The fibrous roots help the cactus absorb water and nutrients from the top layer of the soil.


The flower is one of the world’s most beautiful and unique flowers. They come in a wide variety of colours, shapes, and sizes. These flowers can be white, pink, red, purple, or even yellow. The flower is native to the Americas and can be found in Mexico, the Caribbean, South America, and the United States.

It is also a beautiful sight to behold and they are often vast and showy. The flower blooms for only a few days and then dies, most flowers are pollinated by bees, flies, and other insects.

Adaptations For Water Conservation

This plant has many adaptations for water conservation. It has a very thick skin that helps to prevent water loss and this plant also has small, sharp spines that help shade the cactus’s body and avoid evaporation.

The plant store water in its stem, which can help them to survive for long periods without water. It also has a deep root system that helps to absorb and store water.

Leaves And Spines

Water conservation for the leaves and spines is an essential function. It has many adaptations to conserve water, including the cactus leaves. The leaves are small and close to the ground to reduce evaporation and the spines also help reduce evaporation by providing shade for the body.


Cacti have another interesting adaptation related to water conservation – they can store water in their stems. These characteristic benefits of cacti are living in arid environments where water is scarce. Cacti will quickly absorb and keep as much water as possible in their stems when it rains.


Cacti are plants adapted to survive in hot, dry climates by storing water in their roots. They typically have thick, fleshy roots that help absorb and keep water from rain or morning dew. Some species have shallow root systems that spread out wide to catch as much water as possible when it rains.


The plant has a unique metabolism that allows it to live and thrive in conditions that other plants would not be able to survive in. It can store water in its stem, so it can go for long periods without needing to drink. This helps to stay in hot, dry climates where other plants quickly die of thirst.

It also has a particular type of photosynthesis that allows it to convert sunlight into energy more efficiently than other plants. The plant can grow and thrive even in very sunny, hot conditions.

Taxonomy And Classification

The plant falls under the order Caryophyllales. This vast order also includes beets, carnations, amaranth, spinach, and many other plants. The family contains about 127 genera and over 1750 species.


They are classified as succulents, which are plants that store water in their leaves, stems, or roots. There are over 1,000 different species, and they can be found in various shapes and sizes. Cacti are native to the Americas, and most cacti are found in the desert regions of the United States, Mexico, and Central America. However, cacti can also be found in tropical rainforests and mountains.

Phylogeny And Evolution

All cacti are in the family Cactaceae in the order Caryophyllales. The family is composed of about 127 genera and 775 species.

The phylogeny of cacti remains unresolved, with various molecular data sets producing very different relationships.


Phylogenetic analyses using nuclear ribosomal ITS sequence data suggest that cacti are not monophyletic, instead falling into at least three clades:

  • The first clade consists of the leafless cactoids Pereskia and Maihueniopsis. These two genera are closely related to other Caryophyllales such as Begoniaceae and Portulacaceae.
  • The second clade comprises the “core cacti”, in which the floral tube is derived from an inferior ovary (i.e., it is epigynous). This clade includes all major cactus groups except for Pereskia and Maihueniopsis.
  • The third clade consists of Rhipsalis and Selenicereus, which have tube cacti but are not particularly closely related to the “core cactoids”.

Evolutionary History

The plant is a member of the Cactaceae family, native to the Americas. They first evolved 30 million years ago in the southwestern United States. From there, it spreads to South America and Mexico. Today, there are over 1,500 species of cactus.

The adaptation allows the plant to survive in hot, dry climates. The cactus has several other adaptations that help it stay in harsh conditions, including:

  • Thorns
  • Waxy coating
  • Deep roots

Types Of Cactus You Can Grow At Home

There are many different types of cacti that you can grow at home. Some of the most popular include the following:

Rick Rack Cactus (Selenicereus Anthocyanins)

The rick rack cactus is native to Mexico. It is also known as the zigzag cactus or the fishbone cactus. The rick rack cactus gets its name from its zigzag-shaped stems.

The rick rack cactus is a member of the family (Cactaceae). This type is succulent, which means that it stores water in its leaves and stems. The rick rack cactus is also a climbing cactus. It can grow up to 15 feet (4.5 meters) tall.

Fairy Castle Cactus (Acanthocereus Tetragonus)

The fairy castle cactus is a type that gets its name from its shape, it looks like a castle with many turrets. This is also called the columnar cactus or the Bermuda Triangle cactus.

This type is native to Mexico, Central America, and the Caribbean and it grows in hot, dry climates. It can grow to be 30 feet tall and 6 feet wide.

Golden Barrel Cactus (Echinocactus Grusonii)

The golden barrel cactus (Echinocactus grusonii) is native to Mexico. It is also known as the mother-in-law’s-seat or the devil’s tongue. The golden barrel is a member of the family Cactaceae, which includes about 1,500 species of cacti.

The golden barrel is a popular plant for gardens and landscaping. It is also used in folk medicine. This type has been used to treat various conditions, including colds, headaches, and stomach problems.

Saguaro Cactus (Carnegiea Gigantea)

The saguaro cactus (Carnegiea gigantea) is one of the most iconic cacti in North America. Its tall, columnar shape and large, white flowers are easily recognizable. The saguaro is native to the Sonoran Desert in Arizona, California, and Mexico.

The saguaro can grow over 50 feet tall and live for over 200 years. They are slow-growing cacti, only adding about 1 inch of height each year. The saguaro is an integral part of the Sonoran Desert ecosystem. It provides homes and food for many desert animals, including squirrels, birds, and insects.

Christmas Cactus (Schlumbergera Bridgesii)

The Christmas cactus is tropical that is native to Brazil. It gets its common name from the fact that it blooms around Christmas time. They are succulents, which means they store water in their leaves. Cacti are succulent, but not all succulents are cacti. Christmas cactus plants have stems that are flattened and segmented. These stems grow up to three feet long and are covered in tiny, spiny hairs. The leaves of the Christmas are oval-shaped and have scalloped edges. They are green or reddish-brown.

Star Cactus (Astrophytum Asterias)

This type of plant is a spiny, leafless succulent plant that stores water in its stem. There are about 2,000 species, most of which are native to the Americas. This has been a symbol of desert life for centuries.

The star cactus (Astrophytum Asterias) is a popular species known for its star-shaped appearance. This is native to Mexico and can be found in the wild in arid regions. It has been cultivated for centuries and is a popular houseplant in many parts of the world.

Feather Cactus (Mammillaria Plumosa)

This type is also known as the Mexican cactus or the cactus plumosa. The scientific name for this type is Mammillaria plumosa. This cactus gets its common name from the feather-like spines that cover its body. The spines are modified leaves that help the plant protect itself from predators and to collect water. This has also flowers that bloom in the springtime and are white or pink and have a sweet fragrance.

Old Lady Cactus (Mammillaria Hahniana)

The type is a small, spiny cactus native to Mexico. It has been given its common name because it resembles an older woman with a shawl over her head. This is primarily round and can grow up to 8 inches (20 cm) tall. 

The plant is a popular houseplant because it is easy to care for and does not require a lot of water. It can be grown in a pot or on the ground.

Bunny Ears Cactus (Opuntia Microdasys)

The bunny ears cactus is a type that gets its name from its long, thin leaves resembling a bunny rabbit’s ears. This is native to Mexico and can be found in dry, desert regions. This type is a popular houseplant because it is easy to care for and does not require much water. It has long, thin leaves that are green in colour.

Blue Columnar Cactus (Pilosocereus Pachycladus)

Cacti come in a wide variety of shapes and sizes. This type of cactus gets its name from its tall, slender columns and it can grow up to 20 feet (6 meters) tall and 3 feet (1 meter) wide. This type gets its name from its bluish-green colour. The blue columnar cactus has long, sharp spines that can grow up to 4 inches (10 cm).

Moon Cactus (Grafted Hybrid)

The Moon cactus is a type that has been grafted onto another type. The top part, the “moon cactus” part, does not have chlorophyll and cannot produce its food. The bottom part, the “root cactus,” has chlorophyll and can make its food.

Easter Cactus (Schlumbergera Gaertneri)

The Easter cactus is a beautiful plant that blooms around the Easter holiday. It is native to Brazil and bred as a houseplant in Europe and North America. The plant has long, flattened stems with jointed segments like a cactus. Each piece has 2-4 saw-toothed edges and is covered in small, sharp spines. The flowers of this type are pink, red, or white and have multiple petals.

Lady Finger Cactus (Mammillaria Elongata)

The lady finger cactus (Mammillaria elongata) gets its name from its long, finger-like stems. The cactus can grow up to 12 inches tall and has pink or white flowers bloom in the spring. The lady’s finger is not susceptible to many pests or diseases, but mealybugs can sometimes be a problem. These pests suck the sap out of the plant and can cause it to wilt. Mealybugs can be controlled with a pesticide that is safe for cacti.

Parodia (Various Species)

It is a type that typically grows in the deserts of South America. The cactus has long, sharp spines, and flowers bloom in various colours. They are native to the countries of Argentina, Bolivia, Chile, Ecuador, Peru, and Uruguay. These cacti typically grow in dry, desert climates.

Bishop’s Cap Cactus (Astrophytum Myriostigma)

The Bishop’s cap cactus (Astrophytum myriostigma) is a type of this plant that belongs to the family Cactaceae.  This type gets its common name from its shape, which resembles a bishop’s mitre. It is a small plant that typically only grows to be around 10 cm tall. The Bishop’s cap has a spherical or oval-shaped body with 8 to 12 ribs and its flowers are yellow or white and appear in the summertime.

This type is relatively easy to care for and is a popular choice for gardens or as a houseplant. It does not require much water and can tolerate some neglect. However, it does need to be protected from frost in the wintertime.

Uses of Cactus

Here is some example uses:

Early History

These plants were used for a variety of purposes by early cultures. For example, it was used as a food source by the Aztecs. It was also used as a building material and for making clothing and other items.

It has a long history of use in traditional medicine. It is believed to have been used to treat several conditions, including diabetes, arthritis, and stomach problems.


These plants can be eaten raw or cooked. The most popular type to eat is the prickly pear. It has a sweet and juicy flesh that can be eaten fresh or used in jams, jellies, and other foods.

The leaves are also edible. They can be boiled or fried and are often used as green vegetables in salads, soups, and other dishes.

Psychoactive Agents

The plant is a member of the cactus family, which includes more than 1,300 species. These plants are characterized by their fleshy stems and leaves, which store water to survive in dry climates. Cacti have been used for centuries by native peoples in Central and South America for their psychoactive properties.

The plant contains several psychoactive substances, including mescaline, the primary active compound. Mescaline is a psychedelic alkaloid that produces hallucinations and altered states of consciousness. It is also used as traditional medicine by many indigenous peoples.

Ornamental Plants

These plants can be used as ornamental plants and have been peculiarly successful and are now to be found in all parts of the world where anything approaching a warm climate can be said to exist. They have been introduced into Europe, Australia, South Africa, and many other countries and form an essential part of the floral decoration of gardens and public parks during the summer months.

Interesting Facts

Here are some of the exciting facts about cacti:

  • The cactus is a member of the plant family Cactaceae, which includes about 127 genera and more than 1750 species.
  • The cactus has been used for food, fuel, shelter, and even medicine by native people for centuries.
  • The cactus is a succulent plant that can store water in its leaves, stems, and roots.
  • The cactus is native to the Americas but can now be found in warm climates worldwide.
  • Cacti come in all shapes and sizes, from the tiny Peyote cactus (Lophophora williamsii), which only grows to be about 2.5 cm tall, to the giant Saguaro cactus (Carnegiea gigantea), which can grow up to 15 m tall!

So there you have it, everything you need to know about cacti!

Frequently Asked Questions about this Sharp Plant 

What is special about Cactus?

One thing that makes cacti unique is that they can store a lot of water in their stems and fruits. Their spines are sharp because they evolved that way as a protection against being eaten by animals. Many cacti also have bright flowers that bloom in the evening.

Can a cactus hurt you?

Yes, it can hurt you. The spines are sharp and can easily puncture the skin. If you are unlucky enough to be pricked by one of the spines, it can cause pain, inflammation, and even infection.

How long do Cactus live?

They can live for a very long time, depending on the species. Some can live up to 200 years! They typically have a low growth rate, so they take a long time to grow large. One thing to note is that this can be susceptible to overwatering, so it’s essential only to water them when the soil is dry to the touch. Too much water will rot the cactus roots and cause them to die.

What to do if you touch a cactus?

If you touch a cactus, the first thing you should do is remove any spines from your skin. You can do this by using tweezers or a stiff brush. Once the spines are removed, you should clean the area with soap and water. You can take ibuprofen or acetaminophen if there is any pain or swelling. Finally, you can apply a cold compress if the site is red or sore.

Is there a poison cactus?

Yes, a type of Cactus called the “Arizona Barrel Cactus” secretes a poison known as “mescaline”. It is used in religious ceremonies by some Native American tribes.
The poison causes dizziness, blurred vision, and nausea. In severe cases, it can cause death. If you are bitten or stung by this Cactus, you should seek medical help immediately.

How old is the oldest cactus in the world?

The oldest Cactus in the world is a claret cup cactus, estimated to be around 250 years old. It was discovered in the garden of an ancient monastery in Austria. This plant gets its name from the deep red colour of its flowers, which are only open for one day. It grows slowly, so it’s fortunate that it was found before it was destroyed by development or other human activities.

Is Cactus fruit or a vegetable?

Technically speaking, it is both a fruit and a vegetable. Botanically speaking, the fruit of a cactus is the fleshy structure surrounding the seeds. And while most vegetables are annual plants harvested for their edible leaves, flowers, or stems, cacti are perennial plants harvested for their fruits.

Is all cactus fruit edible?

Yes, all fruit of this plant is edible. However, not all of them are palatable. Some fruits taste sour; others taste sweet. One example of edible fruit is the prickly pear.

Can dogs eat Cactus?

Dogs can eat them, but they should only eat the prickly pear. The other types of cacti are not safe for dogs to eat. Prickly pear cactus is a safe and healthy snack for dogs. It is packed with antioxidants, vitamins, and minerals beneficial for canine health. Prickly pear also contains fibre which helps improve digestion in dogs.

Can you eat cactus leaves Raw?

Yes! Nopales (leaves) are an excellent dietary fibre, vitamin C, and potassium source. They have a mild flavour and can be eaten raw in salads or cooked in stews and other dishes.
One important note: Some people may have an adverse reaction to eating leaves raw, so it’s always best to start slowly and see how your body reacts. Also, since the leaves contain some compounds that can act as natural laxatives, you may want to avoid eating them if you’re constipated.

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