|Christ thorn (large)|
Euphorbia milii, the crown of thorns, Christ plant, or Christ thorn, is a species of flowering plant in the spurge family Euphorbiaceae, native to Madagascar. The species name commemorates Baron Milius, once Governor of Réunion, who introduced the species to France in 1821. It is imagined that the species was introduced to the Middle East in ancient times, and legend associates it with the crown of thorns worn by Christ. It is commonly used as an ornamental houseplant that can be grown in warmer climates. The common name is due to the thorns and deep red bracts referring to the crown thorn Jesus had to wear during his crucifixion and his blood.
It is a woody succulent subshrub or shrub growing to 1.8 m (5 ft 11 in) tall, with densely spiny stems. The straight, slender spines, up to 3 cm (1.2 in) long, help it scramble over other plants. The fleshy, green leaves are found mainly on new growth, and are up to 3.5 cm (1.4 in) long and 1.5 cm (0.59 in) broad. The flowers are small, subtended by a pair of conspicuous petal-like bracts, variably red, pink or white, up to 12 mm (0.47 in) broad. Wat Phrik in Thailand claims to be the home of the world's tallest Christ thorn plant. The plant thrives between spring and summer but produces flowers all year round.
The sap is moderately poisonous, and causes irritation on contact with skin or eyes. If ingested, it causes severe stomach pain, irritation of the throat and mouth, and vomiting. The poisonous ingredients have been identified as phorbol esters. It is very toxic to domesticated animals such as, horses, sheep, cats and dogs. For humans it is mildly toxic and only acts as an irritant.
The plant itself has proven to be an effective molluscicide and a natural alternative to pest control. The World Health Organization (WHO) has recommended the usage of Euphorbia milii in aiding snail control. Especially in endemic countries. Schistosomiasis is an infectious disease from freshwater parasites, carried by snails. Extracts from the plant are used to control the snail population to avoid getting infected from a parasite.
E. milii is a variable species, and several varieties have been described; some of these are treated as distinct species by some authors. E. milii var. splendens (syn. E. splendens) is considered to be the living embodiment of the supreme deity in Bathouism, a minority religion practiced by the Bodo people of Eastern India and Nepal.
- Euphorbia milii var. bevilaniensis (Croizat) Ursch & Leandri 1955
- Euphorbia milii var. hislopii (N.E.Br.) Ursch & Leandri 1955 (syn. E. hislopii)
- Euphorbia milii var. imperatae (Leandri) Ursch & Leandri 1955
- Euphorbia milii var. longifolia Rauh 1967
- Euphorbia milii var. milii
- Euphorbia milii var. roseana Marn.-Lap. 1962
- Euphorbia milii var. splendens (Bojer ex Hook.) Ursch & Leandri 1955
- Euphorbia milii var. tananarivae (Leandri) Ursch & Leandri 1955
- Euphorbia milii var. tenuispina Rauh & Razaf. 1991
- Euphorbia milii var. tulearensis Ursch & Leandri 1955
- Euphorbia milii var. vulcanii (Leandri) Ursch & Leandri 1955
Euphorbia milii can be propagated from cuttings. E. milii is not hardy, and does not tolerate temperatures below 10 °C (50 °F). In temperate areas it needs to be grown under glass in full sun. During the summer it may be placed outside in a sheltered spot, when all risk of frost is absent. The species and the variety E. milii var. splendens have both gained the Royal Horticultural Society’s Award of Garden Merit.
Grown in Malaysia
- Razanajatovo, H. (2020). "Euphorbia milii". IUCN Red List of Threatened Species. 2020: e.T44389A153299391. doi:10.2305/IUCN.UK.2020-1.RLTS.T44389A153299391.en. Retrieved 19 November 2021.
- Ombrello, Dr T., Crown of Thorns, Plant of the Week, UCC Biology Department, archived from the original on 17 September 2009, retrieved 1 October 2009
- Chudasama, C.A.M. (2018). "Molecular marker study in ornamental plant Euphorbia milii". Journal of Pharmacognosy and Phytochemistry. 7 (3). Retrieved 10 December 2020.
- "Crown of Thorns". Retrieved 11 December 2020.
- Huxley, A., ed. (1992). New RHS Dictionary of Gardening. ISBN 978-0-333-47494-5.
- "Crown-of-Thorns (Euphorbia milii)". Veterinary Medicine Library. University Library, University of Illinois at Urbana-Champaign. Archived from the original on 2017-03-23. Retrieved 2017-04-08.
- "Plants Toxic to Animals". Retrieved 18 December 2020.
- Souza, C.A.M. (November 1997). "Study of the embryofeto-toxicity of Crown-of-Thorns (Euphorbia milii) latex, a natural molluscicide". Brazilian Journal of Medical and Biological Research. 30 (11): 1325–32. doi:10.1590/S0100-879X1997001100011. PMID 9532242.
- de Carvalho Augusto, Ronaldo; et al. (July 28, 2017). "Double impact: natural molluscicide for schistosomiasis vector control also impedes development of Schistosoma mansoni cercariae into adult parasites". PLOS Neglected Tropical Diseases.
- Complete Guide to Houseplants. Meredith Publishing Group.
- "RHS Plantfinder - Euphorbia milii". Retrieved 23 February 2018.
- "RHS Plantfinder - Euphorbia milii var. splendens". Retrieved 14 February 2018.
- "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 35. Retrieved 16 February 2018.