However what Darwin did not realise was that Persoon's source of information was in fact Curtis' Flora Londinensis.Going back further in history, high quality images of dissected Primula flowers displaying pin or thrum forms, but never together, include Elizabeth Blackwell's Curious Herbal (1737-39), an image by botanical illustrator Johannes Zorn in Icones Plantarum Medicinalium (1780), and the Flora Danica by German botanist and medical doctor Georg Christian Oeder (1761-1883).These sorts of texts would sometimes also hold information about their magical powers and legends associated with them."Science had clearly moved on by the time of Darwin - but we have traced the origins of his work right back to what we think are the very first observations of heterostyly, some three centuries before his landmark paper."But this work pulls together all the existing documentation, including early floral prints, to trace the history of the idea - over three centuries."Going right back to the 16th century, much of the documentation was in the form of 'herbals' - descriptions of plants put together for medicinal purposes.Documents dating back to the 16th Century provide a unique insight into one of Darwin's landmark studies - according to new research from the University of East Anglia.In 1862, Darwin presented the case that some plant species have two floral forms that differ in height and arrangement of the male and female sexual structures - and adopted the term 'heterostyly'.
Had he done so he would no doubt have cited Curtis' prior observations." The botanist, fungi specialist and in later years poverty-stricken recluse Christiaan Hendrik Persoon is later cited by Darwin as having first observed heterostyly in Primula in 1794.Lead researcher Prof Phil Gilmartin, from UEA's School of Biological Sciences, said: "Darwin is widely recognised as the first to study pin and thrum flowers in Primula and importantly he was the first to provide an explanation for the functional significance of the two types of flower."But while looking through illustrations from the book Flora Londinensis by William Curtis, I was struck by a Primula print which showed the two types of flower captured in a copper plate engraving dating back to the late 1700s.Little did Darwin know that his own grandfather Erasmus Darwin had corresponded directly with William Curtis in November 1781 expressing his delight with the Flora Londinensis 'which he had taken ever since it was published'.Prof Gilmartin said: "It is surprising that Darwin wasn't aware of Curtis' work.