"However, a hypothesis ventured in the 17th c. sounds very plausible to me. One species of wild iris, the Iris pseudacorus, yellow flag in English, is yellow and grows in marshes (cf. the azure field, for water). Its name in German is Lieschblume (also gelbe Schwertlilie), but Liesch was also spelled Lies and Leys in the Middle Ages. It is easy to imagine that, in Northern France, the Lieschblume would have been called 'fleur-de-lis'. This would explain the name and the formal origin of the design, as a stylized yellow flag. There is a fanciful legend about Clovis which links the yellow flag explicitly with the French coat of arms."