Abstract. DELFORGE, P. - The Dactylorhiza of Haute-Marne (52, France): Dactylorhiza devillersiorum sp. nova  [Natural. belges 92 (Orchid. 24): 71-86].
Since 1911, the allotetraploid Dactylorhiza growing in a dozen particular Davall sedge fens with tufa of the Langres Plateau (Champagne-Ardenne, department Haute-Marne, France) was traditionally named D. traunsteineri (s.l.) or, more recently, D. wirtgenii. D. traunsteineri s.s., described from an Austrian fen, seems to be a strictly Alpine species; its origin and main characters do not fit well the Dactylorhiza of Haute-Marne. D. wirtgenii is one of the numerous occasional hybrids D. incarnata × D. maculata s.l. described from marshes of Rhineland-Palatinate one century ago by H…PPNER; this name is not suitable for the Dactylorhiza of Haute-Marne. As no other name seems available, the Dactylorhiza of Haute-Marne is described here as Dactylorhiza devillersiorum sp. nova.

Key-Words: Orchidaceae, Dactylorhiza, Dactylorhiza traunsteineri species group, Dactylorhiza traunsteineri, Dactylorhiza wirtgenii, Dactylorhiza devillersiorum P. DELFORGE sp. nova. Flora of France, Champagne-Ardenne, Haute-Marne.