What Is the Difference Between Geraniums and Pelargoniums?

 What Is the Difference Between Geraniums and Pelargoniums?

The difference between geraniums and pelargoniums is often debated, but fortunately, things are easy to clarify by taking a closer look at both types of plants.
Despite the fact that the terms geranium and pelargonium are often used interchangeably, they are actually completely different plants.
It turns out that most of the plants we commonly call “geraniums” are actually pelargoniums.

Fortunately, the difference between the two becomes very clear when we take a look at some pictures and learn more about these two wonderful plants related to each other.

What Are Geraniums?

Geranium is a plant belonging to the genus of flowering plants, which includes 430 species.

The name geranium is derived from the Greek word géranos, which means "crane." Its English name "crane" is derived from the fact that the fruit capsules of some species are rectangular and resemble the beak of a crane.
As the geranium seed head matures, the “beak” opens, ejecting the seeds some distance for better dispersal.
Geraniums are often referred to as “hardy geraniums” for their ability to tolerate cold weather. This distinguishes them from pelargonium. However, not all geraniums are truly cold hardy.

Physical Markers

The flowers usually have five petals and come in white, pink, purple, or blue. Each petal often has its own specific vein.
Geranium leaves are elongated, almost round in shape, and are botanically described as “palmarate,” meaning they have lobes that arise from a point about halfway up the base.

What Are Pelargoniums?

Most of the plants that many people call "geraniums," including varieties such as zonal, ivy-leaf, and aromatic-leaf, are actually pelargoniums.

Pelargonium (scientific name: Pelargoniums) is a genus of flowering plants that includes 280 species.
The name pelargonium is derived from the Greek term pelargós, which means "stork" because when the flowers form a seed head, they resemble the long, slender beak of a stork, hence the nickname "stork" by early enthusiasts. He also said. .
When the seed heads mature, the seeds are dispersed by the wind. The seeds have a typical spiral shape which increases their ability to penetrate the soil.

Physical Markers

Pelargonium flower heads feature clusters of flowers that open outward from the center. Their flower is somewhat similar to the ribs of umbrellas, hence this type of flower arrangement is called "umbel" from the Latin word umbella, which means "umbrella, canopy".

Pelargonium zoster leaves are usually thick and fleshy and can range in shape from round to lobed. Sometimes the leaves appear dark horseshoe-shaped. Some leaves are also known for their smooth, velvety texture.
Ivy-leaved varieties have leaves similar to ivy leaves and have a waxy coating for improved drought tolerance. As the name suggests, fragrant leaves have a variety of attractive scents.

How All the Confusion Began

Both geraniums and pelargoniums belong to the Geraniaceae family, which consists of 830 species including five genera that are herbaceous or sub-shrubs.

However, although geraniums and pelargoniums belong to the same family, they belong to different genera.

So, if the two plants belong to different genus, why are they often confused? To understand what happened, we have to take a step back in history. This will allow us to finally see how all the confusion began.

Carl Linnaeus, the Swedish botanist, physician, and zoologist known for naming species of organisms, provided binary names for animals and plants.

The first part defines the genus to which this species belongs. The second component gave the precise name that distinguished the species within the genus.  This two-term nomenclature system is called “binomial nomenclature” also known as taxonomy.

For example, we humans are known as Homo sapiens, which was introduced by Linnaeus in 1758. “Homo” indicates that we belong to the genus Homo, while “sapiens” describes this species.

Going back in time, Linnaeus classified both geraniums and pelargoniums under one genus. It took some time to correct this misclassification.

Only in 1789 did the French botanist Charles L. Hertier in the eighteenth century divided them into two different sexes.

For some reason, despite the division, many people still call pelargonium geranium. Although this is not true, many garden centers and nurseries still use the term geranium when marketing their plants because the use of pelargonium can confuse many potential buyers.

Differences Between Geraniums and Pelargoniums

1-Although they belong to the same family (geraniaceae), geraniums and pelargoniums have several differences that set them apart.

2-Geraniums are perennial herbaceous plants that live in the Northern Hemisphere, but are also found in Africa and South America.

3-Pelargoniums are sub-shrubs of the Southern Hemisphere that grow naturally almost exclusively in South Africa.

4-While both geraniums and pelargoniums are mostly composed of 5 petals, morphologically, when looking at the floral symmetry of these plants, we can notice some differences.

5-Floral symmetry describes how a flower can be divided into two or more identical parts in mirror image.

6-Geraniums have actimorphic (star-shaped) flowers. These flowers have five very similar petals and can be divided into 3 or more identical sectors passing through their center and each sector usually contains one petal, one sepal, etc. Another term for this feature is radially symmetrical.

7-Pelargoniums have slightly zygomorphic flowers. These flowers are more asymmetrical, with two upper petals that differ from the three lower petals.

8-Flowers can be divided into mirror-shaped halves by a plane passing through their center, like a person's face.

9-Another term for this feature is unilateral symmetry or bilateral symmetry.

10-As mentioned earlier, the two plants use different seed dispersal techniques: Geraniums distribute their seeds when their beak-like column matures and the springs open, flinging the seeds a distance. While pelargonium seeds are carried by the wind.

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