Euphorbia trigona (African milk weed)
Index
- Pictures
- Identity
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Description
- Plant Type
- Distribution Table
- History of Introduction and Spread
- Habitat
- Biology and Ecology
- Climate
- Air Temperature
- Soil Tolerances
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Causes
- Pathway Vectors
- Impact Summary
- Environmental Impact
- Social Impact
- Risk and Impact Factors
- Uses
- Uses List
- Similarities to Other Species/Conditions
- References
- Links to Websites
- Contributors
- Distribution Maps
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Top of pagePreferred Scientific Name
- Euphorbia trigona Mill.
Preferred Common Name
- African milk weed
Other Scientific Names
- Euphorbia hermentiana LEM.
- Hermentiana triangularis
International Common Names
- English: African milk tree; cathedral cactus; high chaparall
- Spanish: cactus candelabro; candelabra
Local Common Names
- Cuba: corona de la reina
- India: triangular Spurge
EPPO code
- EPHTG (Euphorbia trigona)
Summary of Invasiveness
Top of pageAmong the succulent, cacti-form Euphorbia spp., E. trigona is the most widely grown. It is widely commercialized as an ornamental, hedge plant and potted plant across tropical and subtropical regions. This species has the potential to escape from cultivation. In Cuba and India, where this species has become naturalized, it grows to form thickets in disturbed sites and abandoned gardens in dry and semiarid sites. It mostly spreads vegetatively by cuttings and stem fragments.
Taxonomic Tree
Top of page- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Euphorbiales
- Family: Euphorbiaceae
- Genus: Euphorbia
- Species: Euphorbia trigona
Notes on Taxonomy and Nomenclature
Top of pageThe Euphorbiaceae is a pantropical family, comprising 218 genera and 6745 species (Stevens, 2016). Members of this family are mostly monoecious herbs, shrubs and trees, sometimes succulent and cactus-like plants with xerophytic adaptations (Esser, 2009; Stevens, 2016). The Euphorbiaceae was considered a morphologically well-defined family for a long time, based mostly on their unisex flowers and typical schizocarpous fruits. However, recent molecular studies have resulted in the recognition of several, mostly small families (i.e., Peraceae, Phyllanthaceae, Picrodendraceae, Putranjivaceae). In the most recent circumscription, Euphorbiaceae is defined as clearly monophyletic (Esser, 2009). The genus Euphorbia is among the largest genera of angiosperms, with about 2420 species with remarkably diverse growth forms – such as annual to perennial herbs, thorny/spiny stem or succulents to cactus-like and trees (Horn et al., 2012; Stevens, 2016). Euphorbia trigona is possibly of hybrid origin (PROTA, 2016). There is also an attractive cultivar (Euphorbia trigona cv. Royal Red) with purplish-red stems and leaves.
Description
Top of pageThe following description is adapted from India Biodiversity Portal (2016):
Succulent shrubs or trees, latex milky, branchlets 3-angled, spines 3 mm, divergent, cauducous. Leaves to 2.5 mm, ovate, cauducous. Cyathia solitary or in groups, bracts paired to 3.5 x 4 mm, ovate, obtuse, dentate, glands 5 to 2.2 mm, bracteoles approximately 2.5 mm, obovate, apex fringed; stamens numerous, filaments jointed, 2.6 mm; female flowers erect, ovary about 3.7 mm across, 3-celled, style 3, ovule 1. Capsule to 7 mm, 3-lobed, 3.5 mm, obovoid.
Distribution Table
Top of pageThe distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
Last updated: 20 Apr 2020Continent/Country/Region | Distribution | Last Reported | Origin | First Reported | Invasive | Reference | Notes |
---|---|---|---|---|---|---|---|
Africa |
|||||||
Angola | Present | Native | |||||
Congo, Democratic Republic of the | Present | Native | |||||
Congo, Republic of the | Present | Native | |||||
Gabon | Present | Native | |||||
Malawi | Present | Native | |||||
Asia |
|||||||
Bangladesh | Present | Introduced | |||||
China | Present, Only in captivity/cultivation | Introduced | |||||
India | Present | Introduced | |||||
-Kerala | Present | Introduced | |||||
-Tamil Nadu | Present | Introduced | |||||
Thailand | Present, Only in captivity/cultivation | Introduced | |||||
Europe |
|||||||
Spain | Present, Only in captivity/cultivation | Introduced | |||||
-Canary Islands | Present, Only in captivity/cultivation | Introduced | |||||
North America |
|||||||
Belize | Present | Introduced | Cultivated | ||||
Cuba | Present | Introduced | Invasive | ||||
South America |
|||||||
Colombia | Present, Only in captivity/cultivation | Introduced | Cultivated |
History of Introduction and Spread
Top of pageEuphorbia trigona has been widely commercialized and introduced into many countries to be used as ornamental, hedge and potted plant (Riina and Berry, 2016; USDA-ARS, 2016). However, little is known about the history of introduction of this species. It is commonly planted as a ritual plant and as a hedge and ornamental near villages, especially in tropical Africa. In India, it is described as a “common species” in the deciduous forests of Peninsular India (India Biodiversity Portal, 2016). In Cuba this species was introduced as an ornamental and is now becoming invasive (Oviedo et al., 2012).
Habitat
Top of pageEuphorbia trigona mostly grows in human-made habitats. It also grows in tropical dry forests and dry deciduous forests. In tropical Africa, India and Cuba it is common in disturbed sites, waste areas, roadsides and dry and semiarid environments. In India, it grows in moist and dry deciduous forests from foothills to 400m (India Biodiversity Portal, 2016; USDA-ARS, 2016).
Biology and Ecology
Top of pageGenetics
The chromosome number reported for E. trigona is 2n= 22 (Kothari et al., 1981). Chromosome numbers vary widely across the Euphorbia genus, and aneuploidy and polyploidy have produced speciation events (Perry, 1943).
Reproductive biology
Plants of E. trigona in cultivation rarely produce flowers. In the wild, flowers are small and inconspicuous (India Biodiversity Portal, 2016). It mostly spreads vegetatively by cuttings and stem fragments (PROTA, 2016)
Physiology and phenology
In India, E. trigona has been recorded flowering from December to January and fruiting from February-April (India Biodiversity Portal, 2016).
Longevity
Euphorbia trigona is a moderately fast-growing perennial species. When grown in gardens, in just 3-5 years it will dominate the landscape.
Environmental requirements
Euphorbia trigona prefers to grow in full sunlight conditions, but it can tolerate moderate shade. This species appears to grow on almost any soil with pH ranging from pH 6.1-7.8 (LLIFLE, 2016).
Climate
Top of pageClimate | Status | Description | Remark |
---|---|---|---|
As - Tropical savanna climate with dry summer | Preferred | < 60mm precipitation driest month (in summer) and < (100 - [total annual precipitation{mm}/25]) | |
Aw - Tropical wet and dry savanna climate | Preferred | < 60mm precipitation driest month (in winter) and < (100 - [total annual precipitation{mm}/25]) |
Notes on Natural Enemies
Top of pageEuphorbia trigona is prone to mealy bugs and cactus scale (LLIFLE, 2016)
Means of Movement and Dispersal
Top of pageEuphorbia trigona mostly spreads vegetatively by cuttings and stem fragments (PROTA, 2016). Flowers and fruits are rarely produced. This species is primarily moved/introduced into new habitats by humans (Riina and Berry, 2016; PROTA, 2016; USDA-ARS, 2016).
Pathway Causes
Top of pageCause | Notes | Long Distance | Local | References |
---|---|---|---|---|
Disturbance | Often growing in disturbed sites | Yes | Yes | USDA-ARS (2016) |
Escape from confinement or garden escape | Escaped from gardens/cultivation | Yes | PROTA (2016) | |
Garden waste disposal | Spreads by cuttings and stem fragments | Yes | PROTA (2016) | |
Hedges and windbreaks | Grown as a hedge plant | Yes | Yes | USDA-ARS (2016) |
Internet sales | Widely available online | Yes | Yes | |
Ornamental purposes | Widely commercialized as ornamental, hedge plant and potted plant | Yes | Yes | USDA-ARS (2016) |
Pathway Vectors
Top of pageVector | Notes | Long Distance | Local | References |
---|---|---|---|---|
Debris and waste associated with human activities | Spreads by cuttings and stem fragments | Yes | PROTA (2016) | |
Available for purchase as an ornamental, hedge plant and potted plant | Yes | Yes | USDA-ARS (2016) |
Impact Summary
Top of pageCategory | Impact |
---|---|
Economic/livelihood | Positive and negative |
Environment (generally) | Positive and negative |
Environmental Impact
Top of pageEuphorbia trigona has the potential to displace native vegetation and may form hedge-like barriers in invaded areas. This species has the potential to outcompete native plants for water and nutrients (PROTA, 2016).
Social Impact
Top of pageThe latex of E. trigona is poisonous and caustic for humans, livestock, cats, dogs and wild animals (PROTA, 2016; USDA-ARS, 2016).
Risk and Impact Factors
Top of page- Proved invasive outside its native range
- Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
- Tolerant of shade
- Benefits from human association (i.e. it is a human commensal)
- Long lived
- Fast growing
- Reproduces asexually
- Modification of hydrology
- Modification of nutrient regime
- Reduced native biodiversity
- Threat to/ loss of native species
- Causes allergic responses
- Competition - monopolizing resources
- Competition - smothering
- Poisoning
- Rapid growth
- Rooting
- Produces spines, thorns or burrs
- Highly likely to be transported internationally deliberately
Uses
Top of pageSocial Benefit
Euphorbia trigona is widely commercialized as an ornamental and potted plant and, due to the presence of spines, it is also used as a fence/hedge plant (USDA-ARS, 2016). In tropical Africa, it is commonly planted as a ritual plant and hedge near villages (PROTA, 2016). In India, the sap from the plant is mixed with the mud from termite mounds and is applied on the blades of new knives and axes to sharpen them. The latex is also used as a fish poison (India Biodiversity, 2016).
Uses List
Top of pageEnvironmental
- Amenity
- Boundary, barrier or support
General
- Botanical garden/zoo
- Ritual uses
Ornamental
- garden plant
- Potted plant
- Propagation material
Similarities to Other Species/Conditions
Top of pageEuphorbia species are commonly confused with cacti. However, these two taxa can be easily distinguished by the presence of sticky, milky-white latex in Euphorbia spp., a trait that is absent in cacti. Additionally, the flowers of Euphorbia spp. are usually tiny and inconspicuous while cactus flowers are larger and showy.
References
Top of pageEsser HJ, 2009. Neotropical Euphorbiaceae. In: Neotropikey - Interactive key and information resources for flowering plants of the Neotropics, [ed. by Milliken W, Klitgård B, Baracat A]. London, UK: Royal Botanic Gardens, Kew.http://www.kew.org/science/tropamerica/neotropikey/families/Euphorbiaceae.htm
Esser, HJ, Chayamarit, K, 2001. Notes on Euphorbia (Euphorbiaceae) in Thailand. Harvard Papers in Botany, 6(1), 261-266.
Govaerts, R, 2016. Family Euphorbiaceae - World Checklist of Euphorbiaceae. London, UK: Kew Royal Botanic Gardens.http://apps.kew.org/wcsp/
Kothari NM, Ninant CA, Kuriachan PI, 1981. In Chromosome number reports LXXII. Taxon, 30, 707.
LLIFLE, 2016. Encyclopedia of Succulents. LLIFLE Encyclopedias of Living Forms.http://www.llifle.com/Encyclopedia/SUCCULENTS/
Murillo AJ, 2004. (Las Euphorbiaceae de Colombia). Biota Colombiana, 5(2), 183-200.
Ortiz, DG, 2016. (Plantas ornamentales de la comarca del Camp de Morvedre (Comunidad Valenciana, España)). Revista científica internacional dedicada al estudio de la flora ornamental, 95, 1-10.
Riina R, Berry PE, 2016. Euphorbia Planetary Biodiversity Inventory Project. USA: National Science Foundation.www.euphorbiaceae.org
Distribution References
Esser HJ, Chayamarit K, 2001. Notes on Euphorbia (Euphorbiaceae) in Thailand. Harvard Papers in Botany. 6 (1), 261-266.
Govaerts R, 2016. Family Euphorbiaceae - World Checklist of Euphorbiaceae., London, UK: Kew Royal Botanic Gardens. http://apps.kew.org/wcsp/
Murillo A J, 2004. (Las Euphorbiaceae de Colombia). Biota Colombiana. 5 (2), 183-200.
Ortiz DG, 2016. (Plantas ornamentales de la comarca del Camp de Morvedre (Comunidad Valenciana, España)). Revista científica internacional dedicada al estudio de la flora ornamental. 1-10.
Links to Websites
Top of pageWebsite | URL | Comment |
---|---|---|
GISD/IASPMR: Invasive Alien Species Pathway Management Resource and DAISIE European Invasive Alien Species Gateway | https://doi.org/10.5061/dryad.m93f6 | Data source for updated system data added to species habitat list. |
Contributors
Top of page18/08/16 Original text by:
Dr. Julissa Rojas-Sandoval, Department of Botany, Smithsonian NMNH
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