ipomoea bona-nox

from The Collaborative International Dictionary of English v.0.48

Moonflower \Moon"flow`er\, n. (Bot.)
   (a) The oxeye daisy; -- called also {moon daisy}.
   (b) A kind of morning glory ({Ipomoea Bona-nox}) with large
       white flowers opening at night.
       [1913 Webster]