Adenium Obesum and Adenium Arabicum are two of the most well-known species in the desert rose family. To identify their differences, we can look at the caudex, the leaves, and the flowers. It’s not too difficult at all. Come with us, together let’s explore these two beauties right now.

Caudex

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Arabicum usually has larger caudex than Obesum

As you can see right here, the Arabicum caudex is much bigger or fatter than Obesum caudex. If it is a pure Arabicum without any hybrids, its caudex can grow up to, well if we may put it frankly, the size of a refrigerator.

Obesum caudex is smaller in comparison. It doesn’t look that gigantic. And the caudex gets slimmer on the way up to the branches. The overall look of the Obesum caudex and its branches are quite balanced compared to the Arabicum.

Moving on, let's compare the leaves next:

Leaves

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Arabicum leaves are wider & shorter than Obesum

Arabicum doesn’t usually produce that many leaves and most of them are clustered up on the top branches. Their leaves, however, are wider and shorter than Obesum leaves. On the surface of the leaves, you may find very fine silky hair that can attract insects or spores as well.

Obesum leaves are longer but narrower. They look like a water droplet—the shape you get when you put your index finger against your thumb. The surface of Obesum leaves doesn’t have silky hair. It’s quite waxy and more round near the tip of the leaf.

These two flowers are also a bit different:

Flowers

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Arabicum flowers are smaller & paler than the Obesum

Arabicum flowers are a bit paler than Obesum. The shade is darker around the edges of the petals. At the throat of the flower tube, you will see five distinctive red marks running out about a quarter of an inch or so in the middle of the petals.

Obseum flowers have crimson red color when they are beginning to bloom. The redness fades away over time, leaving us with a nice pink color. The inside tube is yellow with some silky hair near the top of the tube.

Arabicum has only pink flowers. Obesum, thanks to growers' cross-pollination, has many more colors like white, purple, red, and yellow. But not true blue.

And now at this point, can you guess which of the two has bigger seeds? Yes!

Seeds

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As you can probably guess by now, the seeds of Arabicum are bigger and fatter. Seeds of Obesum are usually about an inch or shorter. They are also slimmer than the Arabicum seeds.

The Master's Words

Before going to the comparison table, let us quote the words of an adenium master:

Arabicum flowers are much smaller than Obesum and only pink. Arabicum  body is way chubbier and from it is not growing a trunk but multiple  branches up from that bottom swelling.  Arabicum variety is not in  hybridizing (like Obesum flowers), but selected breading - line breading  - to create types that are: semi-dwarf, dwarf, black or green or brown  skin, branches that grow straight up or horizontal, heavy bloomers ...  
–Garden S

Final Comparison Table: Adenium Arabicum vs Adenium Obesum

Feature Arabicum Obesum
Caudex Big, fatter Smaller, thinner
Leaves Shorter, wider with hairs on the surface Longer, slimmer with waxy surface & no hairs
Flowers Smaller pale pink Bigger pink, red, yellow, white
Seeds Longer, fatter Thinner, short

If you like to explore more about adenium varieties, check out this fantastic book by clicking on the image below:

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So That's The Difference

You see, it's not too difficult to differentiate Arabicum & Obesum desert roses. For us, we remember the Arabicum as the Big Guy.

We don't have a nickname for the Obesum yet, but we're thinking about the Popular Guy, maybe?! Hopefully the post has given you a better idea of how to identify these two species when you get one for yourself.

If you want a much more in-depth look into these two gorgeous beauties, here are:

For an endless exploration into the Adenium family, click this post card right here:

9 Most Popular & Rare Adenium Desert Rose Species List
Check out the most popular adenium desert rose species & how to indentify them for best care

If you have any other ideas, please let us know! With that said, cheers and happy growing.

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