During one of our hikes in Wadi Wurayah, we noticed a remarkable vine spreading across the ground. Its leaves looked familiar, almost like a miniature watermelon plant, but the small round fruits were hard and clearly different from ordinary melons.
The plant was Citrullus colocynthis, commonly known as colocynth, bitter apple, bitter cucumber, desert gourd or vine of Sodom.
Protected-area reminder
Wadi Wurayah is a protected natural area. Access conditions may change, and visitors must follow current official rules. Plants, fruits and seeds should never be collected from a protected habitat.
A desert vine in Wadi Wurayah
At first glance, colocynth can be mistaken for a wild watermelon because it belongs to the same botanical family and has similarly shaped leaves and trailing stems.
The resemblance ends when the fruit is opened. Colocynth pulp is intensely bitter and contains powerful compounds that can cause serious poisoning.
In the desert, a familiar shape does not always mean a familiar food.
What is Citrullus colocynthis?
Citrullus colocynthis belongs to the gourd family, Cucurbitaceae, together with watermelon, cucumber, pumpkin and melon.
It is an accepted botanical species and is native across a broad region extending from the Mediterranean and North Africa through the Middle East and parts of Asia. It is also recorded from the Gulf States and Oman.
An older scientific name sometimes encountered in historical literature is Colocynthis citrullus. Modern botanical references use Citrullus colocynthis.
Common names vary
Bitter apple, desert gourd and vine of Sodom may all refer to this plant. Common names can also be used for other species, so botanical identification should not rely on a name alone.
How the vine grows
Colocynth grows mainly in sandy, arid soils. Its stems spread outward across open ground and may extend for several metres.
When shrubs or other plants are nearby, the vine can climb over them using branching tendrils arising near the leaves. In open areas, it forms a low, sprawling network across sand and gravel.
- Perennial desert plant
- Long trailing stems
- Branching tendrils
- Sandy and arid habitats
- Deep fleshy root
- Small round fruits
Leaves resembling watermelon
The leaves are deeply divided and broadly resemble those of watermelon. They are palmate and angular, commonly with three to seven lobes.
The grey-green surface and divided outline help distinguish the plant from many other low desert vines, although reliable identification should also consider the flowers, fruit and habitat.
Solitary yellow flowers
The flowers are yellow and usually appear singly in the leaf axils—the angle where a leaf joins the stem.
Male and female flowers occur separately on the same plant. Female flowers can be recognised by the small developing ovary beneath the petals, which later forms the fruit.
Flowering and fruit production depend on rainfall, temperature and local conditions. Published descriptions often report multiple fruits on a mature plant, but the exact number varies and should not be treated as a fixed count.
Small fruits with extremely bitter pulp
The fruits are round, smooth and hard, usually much smaller than cultivated watermelons. They may begin green and become yellowish as they mature.
Inside is a pale, dry or spongy pulp containing numerous seeds. The pulp is notoriously bitter and has historically been used as a powerful purgative.
The fruit is potentially poisonous
Eating colocynth pulp or taking concentrated preparations can cause severe abdominal pain, vomiting, profuse diarrhoea, dehydration, bleeding and injury to internal organs. It must not be tasted during a hike or used as a home remedy.
Seeds and traditional food use
The seeds are small, flattened and greyish. Reports commonly describe them as approximately five millimetres long and three millimetres wide, although natural variation occurs.
Colocynth seeds contain oil and protein and have been processed for food or oil in some traditional cultures. However, this does not mean that seeds taken directly from a wild fruit are safe to eat.
Traditional preparation may involve separating the seeds from the toxic pulp, repeated washing, roasting or other processing. The word “egusi” is also used broadly for edible seeds from several African cucurbit species, so it should not be assumed that every product called egusi is this exact species.
Do not eat wild seeds without expert guidance
Seeds may be contaminated with bitter pulp and may be confused with those of other plants. Food use should be limited to correctly identified, professionally processed products from a reliable source.
A large, fleshy perennial root
The plant survives difficult conditions through a large perennial root and long taproot that reach moisture below the surface.
Even when the trailing stems dry or disappear, the underground root may survive and produce new growth when conditions improve.
This deep-rooted strategy allows colocynth to persist in areas where rain is infrequent and surface moisture disappears rapidly.
Why colocynth requires caution
Colocynth has a long history in traditional medicine, particularly as a purgative. Modern case reports document serious poisoning after fruit or herbal preparations were swallowed.
The plant's historical use does not make casual self-treatment safe. Dose, plant part, preparation and individual health can dramatically change the risk.
Anyone who has swallowed colocynth and develops abdominal pain, vomiting, diarrhoea, weakness, bleeding or altered consciousness should receive urgent medical assessment. Do not wait for symptoms to become severe.
- Do not taste the pulp.
- Do not use the fruit for constipation or weight loss.
- Do not give colocynth products to children.
- Do not handle preparations as though they are ordinary food.
- Seek urgent medical advice after suspected poisoning.
How to observe it responsibly
Colocynth is best appreciated where it grows. Photograph the whole vine, leaves, flowers and fruit, but avoid crushing the stems or opening the fruit.
Do not collect plants from Wadi Wurayah or any other protected area. Outside protected sites, local land ownership and conservation rules must still be respected.
- Photograph without uprooting the plant.
- Do not cut or open the fruit.
- Keep children away from fallen fruits.
- Wash hands after accidental contact with damaged pulp.
- Do not publish sensitive plant locations unnecessarily.
- Leave fruits and seeds for the ecosystem.
Final thoughts
Citrullus colocynthis is a striking example of desert adaptation. Its deep root, wandering stems, tendrils and watermelon-like leaves allow it to survive in landscapes where moisture is scarce.
It also demonstrates why hikers should never judge a wild plant by appearance. A small fruit that resembles a melon can contain extremely bitter and harmful compounds.
Observe the desert gourd, photograph it and learn from it—but leave it unopened and uneaten.
Further reading
- Kew Plants of the World Online: Citrullus colocynthis
- Medical case report: colocynth-induced multiorgan toxicity
DubaiHiking.org Editorial Team
DubaiHiking.org shares UAE hiking stories, native-plant encounters and responsible outdoor knowledge from the Hajar Mountains and beyond.
