Historical clue formulations

• Spiny plant — 2024-10-02
• Prickly plant — 2009-12-16
• Flowering plant with prickly leaves — 2006-02-04
• Prickly plant — 2005-03-09
• Thistlelike plant — 2002-07-20
• Prickly-leafed plant — 1999-07-25
• Prickly plant — 1998-07-02