Crown of thorns, (Euphorbia milii), also called Christ thorn, thorny plant of the spurge family (Euphorbiaceae), native to Madagascar. Crown of thorns is popular as a houseplant and is grown in warm climates as a garden shrub. Flowering is year-round but most plentiful in wintertime in the Northern Hemisphere.
Despite its somewhat off-putting name, crown of thorns is a very pretty succulent plant that can bloom almost year-round, even indoors. Although crown of thorns can grow into a woody shrub, it is also an ideal houseplant for most homes. It likes the same room temperature that people enjoy and it can handle the lack of humidity prevalent in most homes during the winter.
The name Crown of Thorns is derived from the belief by some that the crown of thorns worn by Jesus Christ at his crucifixion was made from stems of this plant.
Caution: Besides the sharp black thorns on its main branches and stems, the sticky, latex sap from broken leaves and stems can be a skin and eye irritant. If ingested, all parts of the plant are toxic to people and pets.