Crown of Thorns

Known as Crown of Thorns or Christ plant.
It is a succulent climbing 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 leaves are found mainly on new growth, and are obovate, 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. 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. Wat Phrik in Thailand claims to be the home of the world's tallest Christ thorn plant.