Merriam-Webster Collegiate Dictionary - euphorbia

 noun  Etymology: New Latin, alteration of Latin euphorbea, from Euphorbus, 1st century A.D. Greek physician  Date: 14th century any of a large genus (Euphorbia) of herbs, shrubs, and trees of the spurge family that have a milky juice and flowers lacking a calyx and included in an involucre which surrounds a group of several staminate flowers and a central pistillate flower with 3-lobed pistils; broadly spurge