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 1 m . Carpinus betulusHorizontalis C. betulus [unknown rank] horizontalis Simon-Louis, “ Preisverw., Herbst” 1902–1903 (Simon- Louis 1902). – C. betulus f. horizontalis (Simon-Louis) C.K.Schneid., Illustriertes Handbuch der Laubholzkunde 1: 140 ( Schneider 1904 ) – C. betulus var. horizontalis (Simon-Louis) Bean, Trees and Shrubs, Hardy in the British Isles 1: 294 ( Bean 1914 ). – Original citation: No detailed data given [found by M. Jouin on the Simon-Louis establishments near Metz, France ( Bean 1914 )]. – Type : not localized. – Note: this is a cultivar with a flat crown. The present authors do not have the Simon-Louis catalogue at hand. Depending on whether or not it contains a description and a definite rank, Schneider’s name would become valid when he provided both. If the publication by Simon- Louis constitutes a valid publication with a definite rank, either Schneider’s or Bean’s combination might become superfluous.