1 2 3 4 5 6 7 8 9 On the Origins of Observations of Heterostyly in Primula 10 11 Philip M. Gilmartin1,2 12 13 14 1 School of Biological Sciences, Faculty of Science, University of East Anglia, Norwich 15 Research Park, Norwich, NR4 7TJ. UK. 16 17 18 2 John Innes Centre, Norwich Research Park, Norwich, NR4 7UH. UK. 19 20 For correspondence: Phone: +44(0) 1603 593026 e mail:
[email protected] 21 22 23 Word counts: 24 Abstract, 200 25 Body of text, 7197 26 References, 148 27 Figures 8 (7 colour) 28 Supplemental Figures 7 (All colour) 29 30 31 Key words: floral heteromorphy, Primula, heterostyly, S locus, flower development, 1 32 Summary 33 In 1862, Charles Darwin published his landmark study on the different forms of flower in Primula; 34 he coined the term distyly and subsequently expanded his studies to other species including those 35 with tristyly. Darwin is widely recognised as the first to study pin and thrum flowers in Primula, and 36 to provide an explanation for the functional significance of the two floral morphs. Our laboratory is 37 pursuing the genes that underpin floral heteromorphy in Primula, a study influenced Darwin’s 38 observations. One day, while appreciating a print of Primula vulgaris from William Curtis’ Flora 39 Londinensis, I was struck by the fact that I was looking at images of dimorphic Primula flowers 40 captured in a late-1700’s copper-plate engraving that predated Darwin’s observations by over 70 41 years. This realisation triggered a journey into archives of botanical texts, herbals and florilegea 42 from the 16th to 19th Centuries, and correspondence archives, in search of earlier documents that 43 could have influenced Darwin and the origins of an idea.