Historical clue formulations

• Certain lily — 2018-04-04
• Kind of lily — 2018-02-06
• Showy white flower — 2015-11-06
• Kind of lily — 2013-10-09
• ___ lily — 2012-09-17
• Lily type — 2011-10-02
• Lily variety — 2009-12-13
• Kind of lily — 2004-07-29
• Arum lily — 2003-04-22
• Kind of lily — 2002-10-19
• Lily in a wedding bouquet — 2002-03-29
• Member of the arum family — 2001-11-16
• Plant with heart-shaped leaves — 2000-10-15
• Plant with arrow-shaped leaves — 2000-07-29
• With 35-Across, a sign of spring — 1999-08-29
• Flower with a large white spathe — 1999-01-02
• Showy flower — 1998-06-28
• Kind of lily — 1998-06-08
• Arum lily — 1997-06-04
• Flower with a pure white spathe — 1996-03-09
• White-leafed flower — 1995-10-21
• Arum lily — 1995-07-16
• Arum lily — 1995-02-10
• Plant with arrow-shaped leaves — 1994-07-10
• Greenhouse bloom — 1994-05-15
• Arum lily — 1994-04-06
• "Morning Glory" bloom — 1994-01-22