dahlia: [19] The dahlia was named in 1791 in honour of Anders Dahl, an 18th-century Swedish botanist who discovered the plant in Mexico in 1788. The first record of the term in English is from 1804. During the 19th century it was used for a particular shade of red: ‘One of the many ugly shades that are to be worn this season is dahlia’, Pall Mall Gazette 29 September 1892.
1804, named 1791 by Spanish botanist Antonio José Cavanilles for Anders Dahl (1751-1789), Swedish botanist and pupil of Linnaeus, who discovered it in Mexico in 1788. The likelihood that a true blue variety of the flower never could be cultivated was first proposed by French-Swiss botanist Augustin Pyramus de Candolle, and noted in English by 1835; hence blue dahlia, figurative expression for "something impossible or unattainable" (1866).
