Nomen illegitimum (Latin for illegitimate name) is a technical term used mainly in botany.A nomen illegitimum is a validly published name, but one that contravenes some of the articles laid down by the International Botanical Congress.For example, the family name Salicaceae, based on the "type genus" Salix, was published by Charles-François Brisseau de Mirbel in 1815.So when in 1818 Lorenz Chrysanth von Vest published the name Carpinaceae (based on the genus Carpinus) for a family explicitly including the genus Salix, it was superfluous: "Salicaceae" was already the correct name for Vest's circumscription; "Carpinaceae" is superfluous for a family containing Salix.Carl Linnaeus described what he regarded as two distinct species of grass: Andropogon fasciculatus in 1753 and Agrostis radiata in 1759.