Euphorbia peplus: Characteristics, Uses, Toxicity and Complex Care

Introduction to Euphorbia peplus

Euphorbia peplus, popularly known as milk thirsty, dairy o pigeon, is an annual herbaceous plant belonging to the Euphorbiaceae family. It is recognized by its small size, milky latex, and the toxic potential of the entire plant. It is frequently found in gardens, crops, roadsides, and disturbed soils, especially in damp and shady areas.

Native to Eurasia, this species has become widely naturalized in various regions of the world, including the Americas, Oceania, and temperate zones of Europe and Asia. Its ability to adaptation This makes it a common plant in anthropized environments and an example of a cosmopolitan weed that can impact both agricultural and urban environments.

Common names, taxonomy and etymology

Spanish names: poison basil, coyote herb, evergreen, poisonous basil, poisonous milkweed, wild milkweed, umbrella milkweed, lechibravía, peplos, pichoga, among others.

English names: petty spurge.

Names in other languages: in Portuguese esula redonda, in Asturian lecherina, in Basque esnabedurria, in Catalan lleterola peplus.

Taxonomy: Kingdom Plantae; Subkingdom Tracheobionta; Division Magnoliophyta; Class Magnoliopsida; Order Euphorbiales; Family Euphorbiaceae; Genus Euphorbia; Species Euphorbia peplus.

Etymology: Name euphorbia derives from Euphorbus, physician to King Juba II of Mauretania, who used species of the genus medicinally. The epithet peplus It may come from the Greek "peplos", which means shelter or wrapping, in reference to the structure of its leaves or inflorescences.

Origin, distribution and habitat

Euphorbia peplus It is native to Eurasia, primarily the Mediterranean region and Macaronesia. It has been introduced and naturalized in many parts of the world, including the Americas and Oceania, where it behaves as a ruderal and sometimes invasive species.

• Geographical distribution: Present in Europe, Asia, North Africa, America, Oceania and temperate parts of Mexico, such as Chiapas, Coahuila, Mexico City, Durango, Hidalgo, State of Mexico, Michoacán, Querétaro, Sonora and Veracruz.
• Typical habitats: Gardens, orchards, roadsides, wastelands, nitrified grasslands, ruderalized pastures. It adapts well to shady, moist, and fertile soils, common in temperate and humid zones from sea level to altitudes of 1.600 to 2.800 meters.
• Optimal environmental conditions: It prefers temperate climates and soils rich in organic matter. It tolerates disturbances such as mowing, grazing, and earthworks, which facilitates its expansion.

Botanical description and morphology

• Habit: Annual plant, erect or with somewhat prostrate/procumbent stems, 10 to 50 cm tall (usually between 10 and 30 cm depending on the source), glabrous in all its organs.
• Stems: Highly branched, yellowish-green, densely leafy.
• Sheets: Alternate, petiolate (petiole up to 1 cm), obovate, ovoid, or suborbicular. The blades are 0,5–3 cm long and 0,4–1,2 cm wide, with an obtuse or emarginate apex. The margins are entire, the base is attenuated, and the consistency is thin. The leaves in the inflorescence may be opposite or whorled, becoming wider and shorter at the apex.
• Inflorescence: In cyathia (a characteristic structure of the genus). It appears on the central axis and occasionally on lateral branches. The cyathium measures up to 1,5 mm in length, is campanulate, with yellowish-green glands and white, filiform appendages up to 1,6 mm long. The pleocasium has between 2 and 5 rays (usually 3), which are dichotomized several times.
• Flowers: Male represented by 10-15 stamens, surrounding a single central female flower.
• Fruit: Capsule globular or subglobose, trilobed and depressed, 1,2 to 3 mm, with two membranous keels on each valve and a pedicel of 1 to 3 mm.
• Seeds: Ovoid, white or gray, 1 to 1,7 mm long, slightly hexagonal, with a longitudinal groove and 3-5 dorsal alveoli. Approximate weight 0,6 mg per seed.
• Special features: The whole plant contains latex. white, pungent and milky, highly irritating.

Toxicity and active compounds

Euphorbia peplus it's a plant toxic in all its parts due to the presence of a latex containing di- and triterpenoid esters. These compounds, among which stand out pepluano, jatrophane e Ingenious, determine the degree of irritation and danger of contact with the sap.

• Risks to human health: Latex is irritating and caustic on the skin and mucous membranes (eyes, nose, mouth), which can cause painful inflammation and, if ingested, intense gastrointestinal effects and even death. The plant is included in lists of species whose public sale is restricted or prohibited due to toxicity in many countries.
• Toxicity in animals: If consumed by livestock (cows, sheep, pigs, horses, poultry), it can cause severe poisoning, affect the quality and production of milk, and, in high doses, cause death.
• Highlighted active ingredients: El ingenol 3-angelate, extracted from latex, has shown antitumor activity in experiments and has been the subject of medical research, although the plant is still considered dangerous for direct use due to its caustic properties.

Traditional uses and medicinal applications

• External medicinal use: Latex has been used traditionally, under strict control, to treat injuries dermatological such as warts, calluses, and skin tags. Extreme caution is recommended due to the risk of burns and severe inflammation.
• Other medicinal applications: Some ancient herbal preparations used parts of the plant as an expectorant, anthelmintic, antipyretic, and anti-inflammatory, although today its use is discouraged without professional supervision.
• Risks of self-medication: Home use of latex or extracts can be dangerous and is discouraged for people without experience.
• Other uses: As a weed, it is considered a contaminating plant for crop seeds, which justifies control practices in agriculture.

Phenology, life cycle and ecology

• Life cycle: Annual plant that begins its growth at the end of autumn and flowers in spring, although it can be found in flower throughout the year in mild climates.
• Pollination and dispersal: Mainly allogamous (crossing between individuals) by insects, although wind can facilitate seed dispersal. Myrmecochory (dispersal by ants) is a relevant mechanism. High seed production facilitates rapid proliferation and establishes persistent seed banks in the soil.
• Interaction with the environment: It is a highly adaptable and disturbance-resistant species, capable of easily invading altered or newly formed environments, such as roadsides and disturbed soils.

Similar plants and recognition confusion

• Euphorbia helioscopy y Euphorbia falcata They are species that can be confused due to the similarity in their inflorescences and herbaceous appearance, although they differ in the morphological details of their leaves and fruits.
• For accurate identifications, it is suggested to use photographic resources from herbariums, databases, and specialized botanical identification applications.

Ecological impact and status as an invasive species

• Invasive capacity: Euphorbia peplus is considered a undergrowth in numerous agroecosystems due to its capacity to colonization, high seed production, and rapid establishment in nutrient-rich or disturbed soils. It is specifically mentioned as an invader of roads, orchards, and crops.
• Impact on crops: It can displace desirable species, compete for resources, and affect the yield of other crops. Accidental contamination of agricultural seeds is a major dispersal route.
• Indirect impacts: Its toxicity poses a danger to wildlife and domestic fauna, increasing the need for control measures in rural and peri-urban areas.

Herbicide control, management and resistance

• Control methods: Manual eradication is effective in small gardens, ensuring root removal and preventing seed dispersal. In agriculture, mechanical control is combined with the selective use of herbicides to reduce the effects on crops and the risk of resistance.
• Resistance: Euphorbia peplus shows partial susceptibility to herbicides such as 2,4-D y MCPA in early seedling stages. Integrated management helps prevent adaptation and resistance to chemicals.
• Prevention: Controlling the introduction of contaminated seeds and excessive soil disturbance reduces their proliferation. Maintaining plant cover and competition from desirable species helps prevent their establishment.

Recommendations for cultivation and care in gardens

Although its intentional planting is not recommended due to risks of toxicity and invasive potential, Euphorbia peplus It can be found in gardens as a wild plant. If you want to keep it under control or use it for scientific or ornamental purposes, keep the following in mind:

• Ground: It prefers fertile, moist, and well-drained soils. It tolerates organic matter and some compaction.
• Light: It grows in both sunny and partially shaded areas. In shade, it can develop longer stems and wider leaves.
• Irrigation: It requires a certain degree of humidity, but avoid prolonged flooding.
• Temperature: It tolerates temperate climates, although it can survive mild frosts.
• Pruning and maintenance: If it appears as a weed, pull it out before it fruits to prevent seed dispersal.

Ecological relationships and dispersal

• Myrmecochoria: Seed dispersal by ants (myrmecochory) is a common mechanism. Seeds can also be transported by water, wind, and human activity (farming, earthmoving, etc.).
• Phytosociological behavior: It is a differential species in communities of ruderalized annual plants, appearing alongside species such as middle stellaria, Fumaria muralis, Papaver hybridum and other weeds from orchards and disturbed spaces.

Synonyms and recognized varieties

• Synonymy: Tithymalus peplus, Esula peplus, Keraselma peplus, Euphorbion peplum, Galarhoeus peplus, Euphorbia oleracea, Euphorbia rotundifolia, among other historical and botanical names.
• Varieties:
  • Euphorbia peplus var. minima
  • Euphorbia peplus var. peplus

Useful resources, links and bibliography to delve deeper

Euphorbia peplus It is a plant with a significant impact on biodiversity and agriculture due to its adaptability, toxicity, and ease of dispersal. While its historical medicinal use continues to generate interest, extreme caution must be exercised in its handling and direct exposure to its latex must be avoided. A thorough understanding of its characteristics, dispersal modes, and potential effects is key to its control and to avoiding conflicts with environmental, human, and animal health.

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