Any of several vines of the genus Ipomoea, especially . from 19th c.
1977, Alistair Horne, A Savage War of Peace, New York Review Books 2006, p. 46:Hôtel Saint-George … through whose exotic gardens of giant contorted euphorbia and sweet-smelling moonflowers Churchill and the titans of the Second World War strolled, laying plans for a world in which Anglo-Saxon predominance seemed assured in perpetuity.