Challenges in Typification Within Taxonomically Complex Groups: The Case of the Linnaean Name Centaurea phrygia (Asteraceae)

The Linnaean names have undergone significant changes over time, mainly in taxonomically complex aggregates where hybridisation or genetic introgression are frequent. A notable example is the name <i>Centaurea phrygia</i>, which Linnaeus applied in 1753 in a broad sense, including several taxa that are now recognised as distinct at the specific or subspecific rank. In this context, the typification of the Linnaean name <i>C. phrygia</i> is discussed. The original elements in the protologue, comprising five specimens and one illustration, are critically analysed. The five specimens are excluded for selection as lectotype because they do not correspond to the current concept, use and circumscription of the name <i>C. phrygia</i> subsp. <i>phrygia</i>. The name is lectotypified using an illustration published by Clusius in his "<i>Rariorum plantarum historia</i>". However, the selected lectotype is demonstrably ambiguous, and the name may not be applied to a single currently recognised taxon with certainty. For that reason, <i>C. phrygia</i> may be a clear example for a proposal to conserve the name with a conserved type. However, because the illustration cited by Linnaeus in 1753, and here selected as lectotype, is part of the protologue and therefore cannot be in serious conflict with it or be superseded, we propose a solution to conclusively fix the case of that Linnaean name. Accordingly, we propose an epitype from an element that unambigously represents the current concept and use of the name <i>C. phrygia</i> subsp. <i>phrygia</i>. The epitype selected is a modern and well-preserved specimen kept at PRC (with barcode PRC452350) and with several duplicates.