A synopsis of the genus Enicostema Bl., nom. cons. (Gentianaceae)

In 1759 Linnaeus described an American species under Gentiana, as G. verticillata. In 1781 his son recorded (Suppl. 174) a specimen from India leg. D. D. Fabricius under the same name, without reference to the earlier G. verticillata, and gave a full description. Whether this was just a new record or whether he really intended to describe a new species, which then involves that he was not aware of the name his father had preoccupied, is difficult to prove. No references were mentioned though he gave these elsewhere under other species described before. Though Index Kewensis did not enter this homonym I am rather convinced that it was intended as a new species, also in connection with the fact that he based the description on an Indian specimen. Nomenclaturally this is anyway not very important, but taxonomically it is, because his name and description were made after an Old World species which already Vahl in 1794 (Symb. 3, 46—47) pointed out was different from the American species, without adjusting the necessary nomenclatural consequence. Before Vahl, Retzius had already hinted at this difference (Symb. 2, 1781, 15) in making two varieties under G. verticillatum L. (‘verticillaris’). Even Burman f. (Fl. Ind. 1768, 73) had already remarked that the Coromandel plant differed from the American one figured by Plunder. The distinction of two species was achieved by Willdenow in 1798, who, agreeing with Vahl, at the same time accommodated the two species in the genus Exacum, keeping the epithet verticillatum correctly for the American species and adopting a new epithet hyssopifolium for the Old World ’Gentiana verticillatum L. f.’.