I am fairly certain and that looks like the classic Hymenocallis Tropical Giant whose latin identity is a bit of a mystery. It is grown fairly wide spread in the tropics world wide apparently, including much of the southeastern United States. I saw what appeared to be it in eastern Australia last year, so it gets around. I believe the name was bestowed it by Cecil Houdyshel who distributed it from his California nursery for years. -- Alani Davis