WordNet (r) 3.0 (2006):

evening lychnis
    n 1: bluish-green herb having sticky stems and clusters of large
         evening-opening white flowers with much-inflated calyx;
         sometimes placed in genus Lychnis [syn: white campion,
         evening lychnis, white cockle, bladder campion,
         Silene latifolia, Lychnis alba]