Many people have heard of plants capable of storing water for long periods of time. When you hear of plants like this, one of two names usually comes to mind; cactus or succulents. It is true that the ability to store copious amounts of water is a defining characteristic for both of these plants, so what is the difference between them?
In some context, there actually isn’t any need to distinguish between them, because cactus are a type of succulent; thus the similarity. However, the two names are not interchangeable. All cacti are succulents, but not all succulents are cactus plants.
It is a similar concept as to asking ‘what is the difference between a Doberman and a dog?’ Simple; all Dobermans are dogs, but not all dogs are Dobermans.
There is a factor that makes cactus and succulents a bit more complex, though. In the dog example, you have one large category (dogs) and then many sub-categories that fit perfectly within that larger category (Dobermans, Poodles, etc).
But with succulents, they do not fit into any one plant family. Some of the ‘sub-categories’ they fit into have other plants within their family that are not succulents.
In short, there are many different families of plants that have succulents within them. The cactus is a bit more straight-forward in that all members of the cactus family are succulents.
What Makes a Plant a Succulent?
To put it simply, a succulent is a plant that can hold water for later use. When hearing this, some people may be confused and think that all plants do this. While all plants retain water and use it for sustenance, succulents retain much greater amounts of water within themselves, usually within thick, fleshy leaves, roots or stems.
The purpose of this is that the succulent is actually absorbing more water than it needs right at that moment. The succulent holds onto the water for later use. Succulents tend to be found in parts of the world where water is not readily available, such as the desert, thus the need to hold onto the water for long periods of time.
Cactus plants are among the most famous succulents since they perform this defining characteristic so well, and are able to survive for long periods of time in the driest and hottest parts of the planet.
Telling the Difference Between Cactus and a Succulent
If there are more succulents than just the cactus family, then how does one tell the difference between cactus and other types of succulents?
A common misunderstanding is that the quickest and easiest differentiating factor to notice is leaves. A cactus is said to be one of the very few plants in the world that does not have leaves. With the exception of seedlings; cactus rarely ever have leaves. Instead of leaves, a cactus’ body is covered in thorn-like spines. Other succulents look like a more “traditional” plant, and will have leaves while lacking these unique spines. None of this is true. There are cactii with leaves and succulents without leaves. The true way to spot a cactus is the small pillows that the thorns come out of. If it has those it is a cactus. if not it is a succulent. The pillows does not need to be white as in the image to the left. They can be any color.
The leaves of most succulents will be thick and waxy when compared to most leaves (to help hold water) but they are unmistakably leaves.