Euphorbia milii, with the common names “Crown of Thorns”, “Christ Plant” or “Christ Thorns” hails from Madagascar, a large island situated in the western Indian Ocean, about 225 miles off the east coast of South Africa.
The Latin name, Euphorbia, was coined by King Juba II of Numidia (present day Algeria) after he was treated with a certain potent medicinal plant. He named this plant after his Greek doctor Euphorbus who obtained the plant from Morocco in the Atlas Mountains. King Juba II reigned from between 29 BC-27 BC till his death in 23 AD. However it was only in 1753 when Euphorbia was officially established as the botanical name for this genus of plants in the Euphorbiaceae family.
The label Milii on the other hand, came from the family name of Baron Milius who was then the governor of Reunion, a tropical island located in the Indian Ocean east of Madagascar. He was instrumental in bringing the species to France in 1821 thus Milii was named in his honor.
Interestingly, Crown of Thorns, as commonly called in the English speaking countries, was the plant (branches of this plant) that was braided by the Roman soldiers and placed it on Jesus’ head during His crucifixion - so the legend goes. The original Crown of Thorns are long, malleable, easily woven to create a hoop. According to Dr. T. Ombrello (UCC Biology Dept.), there exist ample proof of the species’ existence in the Middle East even before the time of Christ.
Common names of plants are derived from the plant’s usage in the past, so I have read from botanical books. Sometimes though, as is the case in some countries, a plant can acquire its name through superstitions, legends, folklores. In Thailand, where the plant is extremely popular (thanks to the Chinese who brought the plant to the Island), its name is Poysean, meaning eight saints: Poy being eight and sean being saints. The old E. Milii typically has eight flowers per cluster hence the name, which refers to the eight saints in Chinese mythology. The legend goes to tell that the eight saints sacrificed all their golds, intelligence and spirit to advocate righteousness and justice. By honoring the saints, one will receive good luck according to the specific mythical power of each of the saints: health, bravery, wealth, beauty, artistry, cleverness, poetry and victory over evil spirits.
The Thais highly regard the plant as a lucky charm, a good-luck plant, a symbol of good fortune. They put their potted plants in strategical positions around their houses to invite these positive forces. They believe that the more bloom their Poysean produces, the more luck the household would receive.
References: Crown of Thorns Hybrids by Stephen Jankalski; TropicaNursery.com; www.uaex.edu.,Division of Agriculture, Cooperative Extension Service; Crown-of-Thorns by John McLaughlin and Joe Garofalo; Poysean Hybrids by the Agricultural Extension of the Kasetstart University Faculty of Agriculture, Thailand; WanaplukGardens.com;