Common name Spurge with poisonous and caustic sap (latex) it's not one for a family garden but is very striking.
Some of the common names of various Species give a hint at just how unpleasant these plants can be - Rattlesnake Weed, Medusa's Head, Firestick and Devil's Backbone to name just a few.
That said it's a lovely plant to look at - just remember to keep your distance!!