 In 1719, on the discovery that some species flowered at night, Johann Jacob Dillenius changed the spelling to "Mesembryanthemum" ("flower with the pistil in the center"), rederiving the first part of the word from Greek ("middle") and ("pistil" or "embryo").Carl Linnaeus used the Dillenius spelling (with the "y") in his description of the "Mesembryanthemum" species and the International Code of Botanical Nomenclature requires the retention of the original, deliberate spelling.Mesembryanthemums are often cultivated as ornamental plants for their showy flowers.