Historical clue formulations

• Stem component — 2026-01-02
• Tissue in a plant stem — 2022-04-24
• Plant tissue — 2018-05-04
• Plant tissue — 2014-03-25
• Upward-flowing plant vessels — 2013-02-02
• Woody tissue — 2013-01-09
• Plant tissue — 2012-01-15
• Plant circulatory tissue — 2008-11-30
• Botanical nutrient conductor — 2008-02-23
• Tree tissue — 2007-11-22
• Plant tissue — 2000-10-13
• Plant tissue — 1998-07-30
• Woody tissue — 1995-12-19
• Plant circulatory system — 1995-01-07