Leuzea repens, a new combination (Compositae: Cardueae: Centaureinae)

D. J. Nicholas Hind

doi:10.1007/s12225-019-9809-2

Abstract

SummaryThe taxonomic concepts and nomenclatural issues surrounding a group of taxa, often placed into ‘Rhaponticum Vaill.’ sensu auct. mult., are discussed. Taxonomically, taxa belonging to Acroptilon, Leuzea, Stemmacantha and ‘Rhaponticum Vaill.’, are now considered congeneric. ‘Rhaponticum Vaill.’ is not considered a validly published generic name and taxa are now recognised under the generic name Leuzea, which has priority. The taxonomic position of Acroptilon repens (Compositae: Cardueae: Centaureinae), the only representative of the genus in Iraq, has been reviewed and a new combination in Leuzea is provided, together with an exhaustive synonymy of the taxon concerned.

Highlights

During the initial editing of the draft Flora of Iraq Compositae account, written by several authors some 35 or more years ago, the present author was faced with updating much taxonomy and sorting out many nomenclatural issues with the various scripts
Its toxicity is reported as causing Chewing Disease, a neurological disorder in horses, a response seen to be caused by Centaurea solstitialis L. in the same subtribe (Anon 2015; Vetstream 2014)
Further study indicated that Acroptilon repens belonged to what Susanna & Garcia-Jacas (2006) had termed the ‘III.5.B

Summary

Introduction

During the initial editing of the draft Flora of Iraq Compositae account, written by several authors some 35 or more years ago, the present author was faced with updating much taxonomy and sorting out many nomenclatural issues with the various scripts. Rhaponticum Group’, that in turn formed part of the subtribe Centaureinae This group, of perhaps some 40 species, included the genera Acroptilon, Leuzea DC., ‘Rhaponticum Vaill.’ and Stemmacantha Cass. (Susanna & Garcia-Jacas 2006: 142 – 144; Hidalgo et al 2006) Earlier, in his treatment of the subtribe Centaureinae, Bremer (1994: 149 – 156) recognised a monospecific Acroptilon (A. repens) and Stemmacantha (containing about 20 species); ‘Rhaponticum Hill’ was placed into the synonymy of the latter; two literature references were provided, the first to Holub (1973) and, the second, to Dittrich (1984). Malacophyllum Tausch along with several species belonging to Rhaponticum sensu auct., synonymising all, reducing the genera to subgenera of Leuzea and providing many new combinations In his discussions on the nomenclature, he highlighted and summarised the many issues with the generic name Rhaponticum, concluding that it should only be ascribed to Ludwig, and considered synonymous with Centaurea L.; the present author concurs with this view. The ‘Rhaponticum group’ was clearly comprised of the concepts of Acroptilon, Leuzea and ‘Rhaponticum Vaill.’

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