No taxon left behind? - a critical taxonomic checklist of Carpinus and Ostrya (Coryloideae, Betulaceae) Author Holstein, Norbert Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Nordrhein-Westfalen, Germany. & Corresponding author: holstein @ uni-bonn. de Author Weigend, Maximilian Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Nordrhein-Westfalen, Germany. & Email: mweigend @ uni-bonn. de text European Journal of Taxonomy 2017 2017-12-07 375 1 52 journal article 21949 10.5852/ejt.2017.375 c072dbcc-028b-4fa2-a564-8601e0435854 2118-9773 3838542 1d. Carpinus betulus ‘ Heterophylla ’ C. betulus var. heterophylla G.Kirchn., Arboretum Muscaviense : 667 ( Petzold & Kirchner 1864 ). – C. betulus f. heterophylla (G.Kirchn.) K.Koch, Dendrologie 2 (2): 3 ( Koch 1873 ). – Original citation: No detailed data given. – Type : not localized. – Note: Kirchner gave the name “ heterophylla ” to plants that have both normal-shaped leaves and deeply serrated leaves, regardless whether the leaf serration is of the ‘Incisa’ or ‘Quercifolia’ type , which he regarded as synonymous, as did Koch. As the mutation occurs spontaneously and may be fixed by cuttings, this name ‘Heterophylla’ is complicated to use. Kirchner refers to “Bth. cat.”, meaning the catalogue of James Booth and Söhne nursery in Klein-Flottbek, Hamburg , Germany . As there is no reference to Loudon, Kirchner’s name cannot be regarded as a clear recombination of C. betulus var. heterophylla hort. ex Loudon , which is an invalid name published as a synonym of C. betulus ‘Quercifolia’. Therefore, Kirchner’s name is not illegitimate, but rather a later homonym.