Charles de l’Écluse, L’Escluse, or Carolus Clusius (February 19, 1526 – April 4, 1609), seigneur de Watènes, was a Flemish doctor and pioneering botanist, perhaps the most influential of all 16th-century scientific horticulturists.
Clusius helped create one of the earliest formal botanical gardens of Europe at Leiden, the Hortus Academicus, and his detailed planting lists have made it possible to recreate his garden near where it originally lay.
In the history of gardening he is remembered not only for his scholarship but also for his observations on tulips “breaking” — a phenomenon discovered in the late 19th century to be due to a virus — causing the many different flamed and feathered varieties, which led to the speculative tulip mania of the 1630s. Clusius laid the foundations of Dutch tulip breeding and the bulb industry today.
His contribution to the study of alpine plants has led to many of them being named in his honour, such as Gentiana clusii, Potentilla clusiana and Primula clusiana. The genus Clusia (whence the family Clusiaceae) also honours Clusius.