Carpobrotus edulis

Carpobrotus edulis

The hottentot fig, sour fig, ice plant or highway ice plant (Carpobrotus edulis (L.) N.E.Br.) is a succulent species belonging to the Aizoaceae family.

Systematics –
From a systematic point of view to:
Eukaryota domain,
Kingdom Plantae,
Magnoliophyta division,
Class Magnoliopsida,
Order Caryophyllales,
Aizoaceae family,
Genus Carpobrotus,
C. edulis species.
The term is basionym:
– Mesembryanthemum edule L..
The terms are synonymous:
– Abryanthemum edule (L.) Rothm.;
– Carpobrotus edulis (L.) L. Bolus.
Within this species the following subspecies are recognised:
– Carpobrotus edulis subsp. edulis;
– Carpobrotus edulis subsp. parviflorus Wisura & Glen.

Etymology –
The term Carpobrotus comes from the Greek καρπός carpόs fruit and βρωτός edible brōtós: for the edible fruit.
The specific edulis epithet comes from édo to eat, therefore edible.

Geographic Distribution and Habitat –
Carpobrotus edulis is a plant native to the Cape Provinces, in South Africa.
This plant has been introduced to other countries and has naturalized in many other regions of the world, becoming an invasive species in several parts, particularly Australia, California and the Mediterranean, all of which have similar climates.
This plant has escaped cultivation and has become invasive, posing a serious ecological problem by forming large monospecific zones, lowering biodiversity and directly competing with various threatened or endangered plant species for nutrients, such as water, light and space.
It is located at Cape Angela in Bizerte, Tunisia, near the Mediterranean Sea.
In Ireland it has escaped cultivation in County Down in the south and east and on the cliffs of Howth Head in County Dublin.
On the Mediterranean coast it spread rapidly and now parts of the coast are completely covered. Additionally, another invasive species, the black rat, has been shown to promote the spread of the ice plant through its feces. Since the ice plant represents a food source for the rat, both benefit from each other, which is referred to as invasive mutualism.
In New Zealand it forms monocultures and has occupied large areas of the coastal sand dune ecosystem. C. edulis and its hybrids are classified as unwanted organisms and are listed under the National Pest Plant Accord.
In the United States, although this plant may have arrived by ship as early as the 16th century, it was actively introduced in the early 1900s to stabilize dunes and soil along railroad tracks; it was later used by Caltrans for ground cover along highway levees. In addition, thousands of acres were planted in California up until the 1970s. In California it is found in coastal habitats north of Eureka, south at least to Rosarito in Baja California.
In Italy it is naturalized in Sicily, Sardinia, Calabria, Campania, Tuscany, Liguria, Puglia, Molise, Lazio, Marche and Abruzzo.
Its habitat is that of the sandy or rocky coasts where it is present in large patches covering the dunes and the beaches close to the sea, thanks to the robustness and resistance to the brackish conditions up to a maximum of 500 m. a.s.l..

Description –
Carpobrotus edulis is a perennial, succulent and creeping plant that grows up to 15 – 20 centimeters in height, spreading spontaneously forming grassy carpets, so when cultivated it lends itself to decorating gardens or entire rocky walls.
The roots are thin and branched.
The stem is branched dichotomous (repeated ramifications in two equal parts) and contains, like the leaves, a dense and viscous sap which constitutes a reserve in times of drought.
The leaves are fleshy claw-shaped, 8 – 12 cm. and triangular in section and green in colour. These are often upright, tapering from root to apex. In conditions of prolonged exposure to sunlight they can take on a reddish color near the edges.
The flowers are characterized by corollas that open during the sunniest hours of the day. The flower is solitary, with a small head, with a short peduncle, lasting about ten days, very decorative, of about 4 cm in diameter; the color is antique pink, with 20-80 petals gathered at the button and 30-40 stamens. The set of calyx and corolla, which constitutes the perianth, is formed by 5 tepals of the same structure as the leaves; what appears as a colorful corolla is nothing more than a set of sterile stamens with the shape and consistency of colored petals; the fertile stamens are always yellow. The stigmas are arranged in a circular pattern in the gynoecium.
The anthesis is between May until the end of October, also depending on the latitude.
The fruit is a pod, yellowish, subglobular, with a diameter of 20 – 35 mm, indehiscent, which has a coarsely papillate capsule.
The seeds are dark, wrinkled with small tubercles and reside in a gelatinous mucilage. The ripening fruit turns yellow giving off a characteristic scent. This is edible and sour in taste.

Cultivation –
Carpobrotus edulis is a succulent perennial plant that forms a dense growth carpet that completely covers the soil.
The plant is sometimes harvested from the wild for its medicinal uses and edible fruit, while it is also grown both as an ornamental and for its ability to stabilize sandy soils or in stony walls.
This plant is a subtropical species of mainly coastal regions. It can occur in the drier parts of the tropics and subtropics, and also in the hotter parts of the temperate zone. The plants are not very cold tolerant and cannot tolerate temperatures below about -2 °C.
For their cultivation they require a well-drained sandy soil in a sunny position.
The plants can be grown on dry stone walls or in flower beds and are very resistant to drought, wind and salt.
For this reason, Carpobrotus edulis is widely cultivated as an ornamental and ground cover plant. In cultivation, yields of 1,700 kilos per hectare were achieved.
Many varieties have been introduced and grown as ornamental plants for the spectacular and splendid colors of their flowers: all shades of red, pink, white, yellow and orange.
However, it has often escaped cultivation, especially near the coast, and can spread readily and rapidly to form deep, dense mats that smother other low-growing native vegetation.
The plant can also cause changes in soil pH.
Propagation can be by seed. In this case the lower night temperatures are beneficial. The seed usually germinates in 7 – 10 days at 23°C.
Once grown in pots or in a nursery they can be planted in the open field.
It can be propagated asexually using cuttings at any time during the growing season. In this case it is recommended to let the cutting dry in the sun for a day or two and then pot in a very sandy mix.
The flowers are pollinated by entomochora and various organisms feed on its fruits, thus contributing to the dispersion of the seeds and the spread of the plant: rodents, ungulates and primates. Tortoises, on the other hand, feed on the vegetative parts.
Given its high adaptability and ability to reproduce in a vegetative way, in places of introduction it can easily become a weed, harmful to the native plant species, with which it competes for space. This is demonstrated by extensive carpets that cover entire dunes.
However, some positive sides of the presence of C. edulis can be the stabilization of the soil, its being a reserve of liquids where water is in limited availability, it creates a suitable barrier against fire and in large quantities it can be transformed in quality fertilizer.

Customs and Traditions –
Carpobrotus edulis is a plant whose various parts have been used in its places of origin, in South Africa, both in traditional medicine and for food use.
In the fifteenth century, in South Africa, it was the settlers who, seeing the local populations (the Khoi) eat the fruits as if they were figs, called it “Fico degli Hottentots”.
It takes various names according to the areas where it grows: hottentot fig, sour fig, ice plant, highway ice plant, uña de gato, etc.
In Sicily, where it is widespread in various areas of the south-western coast, it is also known as varva di monacu (monk’s beard in Sicilian).
In edible use, both raw and cooked or dried fruits are used for later use or transformed into pickles, etc.; even the flowers are edible.
The fruit contains very little pulp and must be fully ripe otherwise it is very astringent.
When ripe it is mucilaginous and sweetly acidic.
Even the leaves are edible both cooked and raw; they are succulent and are eaten in salads and can also be used as a substitute for pickled cucumbers.
In medicinal use, the leaves are used which are highly astringent, mildly antiseptic, diuretic, constipated.
It is probably the tannins contained in this plant that are responsible for many of the beneficial properties.
The juice of the leaves is taken orally to treat dysentery, diarrhea and other digestive problems.
A mixture of leaf juice, honey and olive oil in water is an old remedy for tuberculosis.
The tips of the leaves are chewed, swallowing the juice to relieve the sore throat; for this reason, only the juice of the leaves is used in gargles to treat infections of the mouth and throat.
The same juice is applied topically as a soothing lotion to treat bruises, grazes, wounds, burns, eczema, sunburn, ringworm, diaper rash, chapped lips, toothache, earaches, oral and vaginal thrush.
The leaf pulp is applied as a poultice on wounds and infections.
The juice of the leaves or a crushed leaf is a popular soothing cure for insect bites.
According to some reports, a syrup made from the fruit is said to have laxative properties, and it is an ancient and apparently very powerful remedy for constipation to eat fruit and then drink brackish water.
Among the others, the agroforestry ones are mentioned. Plants of this genus are vigorous and prostrate in growth, producing a dense carpet of foliage and making a very effective ground cover. They can be planted in maritime zones, especially in Mediterranean climates, in order to prevent the soil erosion in the sandy soils, dunes and on the banks, even if their introduction must be carefully evaluated in order not to destabilize the natural habitats.
The plant has very fleshy leaves and is moderately resistant to fire. It can be used in barrier plantings to prevent the spread of forest fires.
However, the practices described are not yet accepted by medicine, as there is not enough scientific and experimental evidence, so they could be ineffective or harmful to health.
From a biochemical point of view, the dried leaves contain about 19.4% of tannin and the dry stems 14.2%.
C. edulis contains rutin, neohesperidin, hyperoside, catechin and ferulic acid; these contribute to the antibacterial properties of the plant. It also contains procyanidins and propelargonidins.
From an ecological point of view, the flowers are pollinated by various bees and many species of beetles. The leaves are eaten by turtles. The flowers are eaten by antelopes and baboons. The fruits are eaten by baboons, rodents, porcupines, antelopes, which also disperse the seeds. The tufts provide shelter for slugs, lizards and skinks. Adders and other snakes, such as the Cape cobra, are often found in Carpobrotus tufts, where they ambush small rodents attracted by the fruit.

Method of Preparation –
Carpobrotus edulis is a plant used historically, in its places of origin, for both food and medicinal purposes.
As mentioned, both the leaves, the fruits and the flowers can be eaten raw or cooked.
In South Africa the ripe fruits of the sour fig are harvested and eaten fresh or made into a very tart jam.
The flowers are suitable for preparing jams with a sour and slightly salty taste.
In the medicinal field, the leaves can be ingested orally for digestive problems or the juice can be inhaled to relieve sore throats.
The juice can also be mixed into a base lotion and used for external problems like ringworm, bruises, sunburn, and chapped lips.
The liquid extracted from the leaves is used as a soothing agent for redness, skin irritation, sunburn, eczema, abrasions, lip herpes, dryness of the mucous membranes of the lips. It is effective as a pain reliever and anti-inflammatory against lesions caused by jellyfish attacks and soothing against insect bites; these properties earn it the title of first aid plant.
The extract is antiseptic and astringent, properties that make it suitable for the treatment of gastrointestinal pathologies: laxative against constipation, both in people and livestock, administered with fruit and sea water. Mixed with water it lends itself to reducing diarrhea, dysentery, stomach cramps. It is suitable for the reduction of inflammation of the mouth and throat (laryngitis).
In South Africa, where this plant originated, it is used for the treatment of tuberculosis and as a therapeutic treatment for diphtheria and diabetes. It is also used as a pain reliever in affected areas and as a skin emollient.
Finally, popular belief attributed particular virtues by spreading it on the head of newborns to make them strong and vigorous.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora of Italy, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.

Photo source:
– https://inaturalist-open-data.s3.amazonaws.com/photos/254201520/original.jpeg

Attention: The pharmaceutical applications and alimurgical uses are indicated for informational purposes only, they do not in any way represent a medical prescription; we therefore decline all responsibility for their use for curative, aesthetic or food purposes.