OXALIS PES-CAPRAE: CHARACTERISTICS, HABITAT, USES, CARE - BIOLOGY - 2025

Oxalis pes-caprae is a perennial herbaceous plant considered weed that belongs to the Oxalidaceae family. Commonly known as citrus, agrillo, canary, chives, sleepers, dream flower, matapan, clover or vinagrillo is a native herb of South Africa.

It is a creeping perennial herb 10 cm high, with a low branching deep root covered by numerous bulblets. The petiolate and trifoliate leaves with heart-shaped lobes are bright green and have small scattered brownish-black macules.

Oxalis pes-caprae. Source: Zachi Evenor

The bright yellow single or double bell-shaped flowers are grouped in racemose inflorescences or umbels at the end of a long floriferous stem. Flowering occurs during spring and fall; fruiting is occasional outside its natural habitat.

It is an invasive growing plant with abundant underground bulbils that favor its vegetative propagation. It grows on humid and shady soils, in ruderal or abandoned lands, fields, along fences or roads. In some environments it is considered a weed, but it is often used in gardening.

The leaves are consumed as a dressing in salads and used as a medicinal plant due to its antiscorbutic, antipyretic and toning properties. In the dyeing industry, the intense yellow flowers are used as an alum mordant to dye wool.

General characteristics

Appearance

Acaulean herbaceous plant of low bearing and creeping growth, it measures 6-10 cm in height and can reach up to 25-30 cm when it blooms. It has an extensive underground rhizome with abundant bulblets 6-10 mm in diameter, which allows the annual proliferation of the plant.

Leaves

The trifoliate leaves with bilobed segments, slightly succulent and hairy margins, are located on a long petiole with small glandular trichomes. The glossy dark green leaflets are irregularly covered by small dark spots or dotted spots on both sides.

flowers

Simple flowers of radial or actinomorphic symmetry have 5 obovate, bright yellow petals 2-2.5 cm long and united at the base. The inflorescence is an umbel of 1-20 flowers arranged terminally on a smooth peduncle 5-35 cm long.

Oxalis pes-caprae flowers. Source: MathKnight and Zachi Evenor אביר המתמטיקה וצחי אבנור

Fruit

The Oxalis pes-caprae species is characterized by producing ripe fruits in their natural habitat or only when environmental conditions are suitable. The fruit is a loculicidal and pubescent cylindrical capsule 6 mm long, with 3-4 globular seeds per loculus of brown color.

Chemical composition

Its main active component is oxalic acid, which can be toxic to both man and animals. Also, its soluble salt or potassium oxalate easily combines with calcium and magnesium in the blood, causing hypocalcemia in those who consume it.

The decrease in available calcium in the blood serum can lead to deterioration of the cell membrane. In this case, the symptoms manifest as tremors in the upper and lower extremities, dizziness and muscle weakness.

Taxonomy

- Kingdom: Plantae

- Division: Magnoliophyta

- Class: Magnoliopsida

- Order: Oxalidales

- Family: Oxalidaceae

- Genus: Oxalis

- Species: Oxalis pes-caprae L., 1753.

Etymology

- Oxalis: the name of the genus is the composition of the Greek terms "oxys" which means acid and "hals, halós" which means salt. Alluding to the acidic and salty taste of its leaves.

- pes-caprae: the specific adjective is the combination of the Latin terms «pēs, pědis», which means foot, and «caprae» which means goat. In relation to the characteristic shape of the leaflets of its leaves.

Leaves of Oxalis pes-caprae. Source: Daniel Feliciano

Synonymy

- Acetosella abyssinica (Walp.) Kuntze

- Acetosella cernua (Thunb.) Kuntze

- A. ehrenbergii Kuntze

- Bulboxalis cernua (Thunb.) Small

- Jonoxalis pes-caprae (L.) Small

- Oxalis biflora Burm. fil.

- Oxalis cernua Thunb.

- O. cernua f. microphylla Batt.

- O. cernua var. Lowe pleniflora

- Oxalis concinna Salisb.

- Oxalis ehrenbergii Schltdl.

- O. libyca Viv.

- O. lybica Willk. & Lange

- Oxalis mairei Knuth ex Engler

- Oxalis pes-caprae var. pleniflora (Lowe) White-God

- O. pes-caprae f. pleniflora (Lowe) Sunding

- O. pleniflora Lanfranco

Habitat and distribution

The vinagrillo is a plant native to southern Africa, endemic to Namibia and the Cape region of South Africa. Due to its high colonization capacity, it has been introduced in North Africa, the Mediterranean basin, North America, Mexico, Australia and New Zealand.

It is considered a weed or weed plant of cultivated fields, reed beds, humid and shady environments, ruderal lands and wooded areas. As an ornamental plant, it is widely cultivated due to its ease of propagation vegetatively, from sea level to 800 meters above sea level.

It is a nitrophilic species that invades citrus groves, where it forms a tapestry that completely covers the entire surface of the land. Its form of dispersion is through the bulblets in the rhizomes, transported by the removal of contaminated soil, garden waste or agricultural implements.

During the summer it goes into estivation or lethargy, the foliar area dries up in late spring and the underground bulblets re-sprout in early autumn. This rest during the summer allows it to survive in extremely dry and hot environments characteristic of the Mediterranean basin.

The ideal environments for its cultivation are the mild climates near the coast with constant humidity in the land. Hence its inclination to colonize citrus plantations in the Mediterranean regions.

Roots of Oxalis pes-caprae. Source: No machine-readable author provided. Daniel Feliciano assumed (based on copyright claims).

Applications

Medicinal

The presence of oxalic acid gives it certain medicinal properties with an anti-inflammatory, antiscorbutic, antipyretic, diuretic, purifying, refreshing and invigorating effect. In addition, it contains anthraquinones, minerals, mucilages, acid salts such as potassium oxalate or sorrel salt and vitamins, especially vitamin C.

Its consumption is restricted since its high content of oxalic acid can be toxic to man and animals. The accumulation of potassium oxalate in the body can lead to the formation of stones in the urinary tract or kidney.

Oxalic acid poisoning can cause nausea, sore mouth and throat, abdominal pain, tremors, low blood pressure, and a weak pulse. High doses can lead to kidney disorders, liver and kidney damage, seizures, fainting, and even death in chronic patients.

Topically, the decoction of leaves and roots is used to relieve abscesses, dermatoses or small mouth ulcers. It is recommended to ingest the extract of the fresh plant to combat the first stages of ulcers or cancerous tumors in the stomach.

It is contraindicated in patients with kidney or urinary tract diseases, with lithiasis and symptoms of gout. Its frequent consumption in high doses can cause kidney damage and chronic poisoning.

Ornamental

It is widely cultivated in parks and gardens because it fully covers the surface and when it blooms it displays a wide range of yellow flowers. As an ornamental it is sown on flower beds, rockeries and pots, although it requires effective management and control to prevent it from becoming an invasive plant or weed.

Oxalis pes-caprae bulbs. Source: No machine-readable author provided. Daniel Feliciano assumed (based on copyright claims).

Industrial

The flowers are used for dyeing, alum being used as a mordant and providing an intense yellow color to wool.

Agroforestry

In some regions it is used as a plant cover for citrus beds, in order to protect its roots from frost. In addition, it serves as a cushion so that the falling fruits do not spoil when they fall to the ground.

Nutritional

In some regions, its flowers and leaves are consumed fresh, raw or cooked, as a salad dressing due to its pleasant bitter taste. The leaves and branches are used to prepare sauces to flavor roast meats and grilled fish.

The small bulblets seasoned with oil and lemon are eaten roasted on the grill. On the other hand, it is used in small quantities as a nutritional supplement for livestock, although it is considered toxic in rabbit farming.

Melliferous

Bees are attracted to its pleasant nectar.

Oxalis pes-caprae in its natural habitat. Source: Robert Flogaus-Faust

Care

Multiplication

The propagation of the vinegar is carried out exclusively by cuttings of the rhizomes or division of plants at the end of winter. The presence of bulblets on the roots facilitates their dispersal, since these small tubers produce leaf stalks in early fall.

Floor

It grows on any type of soil, preferably sandy-loam and with a high content of organic matter. It requires permeable and well-drained soils.

Irrigation

Frequent waterings are recommended without flooding, trying to keep the soil moist, especially at the beginning of flowering. After flowering, the frequency of watering should be reduced, until completely restricted during winter.

Driving

The application of organic fertilizers at the time of establishing the plantation will allow to obtain healthy and productive plants. The maintenance and training pruning are essential to avoid its dispersion in the neighboring lands.

Rusticity

Plant adapted to full sun exposure or partially shady conditions, tolerates strong frosts down to -15 ºC. However, it does not support strong summers so it must be placed under shade or in the undergrowth.

Plagues and diseases

The Oxalis pes-caprae species is a fairly rustic and resistant plant that has no reported major pest or disease problems. However, under adverse conditions it may have a certain incidence of pests or pathogens common to ornamental garden plants.

References

1. Bissanti, G. (2019) An Ecosustainable World: inside i codici della Natura. Recovered in: antropocene.it
2. Castro, S., Ferrero, V., Costa, J., Sousa, AJ, Castro, M., Navarro, L., & Loureiro, J. (2013). Reproductive strategy of the invasive Oxalis pes-caprae: distribution patterns of floral morphs, ploidy levels and sexual reproduction. Biological Invasions, 15 (8), 1863-1875.
3. Güçlütürk, I., Detsi, A., Weiss, EK, Ioannou, E., Roussis, V., & Kefalas, P. (2012). Evaluation of anti-oxidant activity and identification of major polyphenolics of the invasive weed Oxalis pes - caprae. Phytochemical analysis, 23 (6), 642-646.
4. López Espinosa, JA (2019) vinagrillo. Oxalis pes caprae (Oxalidaceae). Region of Murcia Digital. Recovered at: regmurcia.com
5. Oxalis pes-caprae (2019) Wikipedia, The Free Encyclopedia. Recovered at: es.wikipedia.org
6. Oxalis pes-caprae L. (2018) Catalog of Life: 2019 Annual Checklist. Recovered at: catalogueoflife.org
7. Puccio, P. (2003) Oxalis pes-caprae. Monaco Nature Encyclopedia. Recovered at: monaconatureencyclopedia.com
8. Tola, G. (2016) Species file Oxalis pes-caprae. Invasive Exotic Species of the Iberian Peninsula. Recovered at: invasiber.org