A large family of dicotyledonous plants, mainly tropical in distribution, containing over 5000 species in some 300 genera. It is commonly known as the spurge family. Most members have simple alternately arranged leaves and unisexual flowers. In the tribe Euphorbieae the small flowers are grouped into an inflorescence, which, due to the presence of various petal-like structures (e.g. highly coloured bracts and glandular appendages), resembles a single flower. The 'flowers' of poinsettia (Euphorbia pulcherrima) are examples. The specialized inflorescence of Euphorbia species is termed a *cyathium
. The fruit is often a regma and in many genera the seeds are carunculate. The family contains many commercially important species including Hevea brasiliensis, the main source of natural rubber, Manihot esculenta (cassava), and Ricinus communis (castor oil).