Abstract: Delforge, P. & Gvaudan, A.- Epipactis maestrazgona sp. nova, a species of the Epipactis leptochila species group, endemic of the Iberian Meridional System (province of Teruel, Aragon, Spain) [Natural. belges 85 (Orchid. 17) (2004): 49-71]. Epipactis provincialis Aubenas & Robatsch 1996 is a well delimitated early-flowering xerophilous species of the E. leptochila species group growing at a height of 200-500 m in Provenal thermophilous Quercus pubescens woods and associated garrigues. Recently, some records of Epipactis provincialis were made in the central Iberian Peninsula at a height of 1400-1600 m, growing in cold places of Pinus sylvestris forests of the Sierra de Gdar (province of Teruel, Aragon). Personnal field research carryied on in France and Spain has shown that the Spanish entity, isolated in the meridional Sistema Ibrico, represents another species of the Epipactis leptochila species group, late‑flowering, sciaphilous, not yet named. It is described here as Epipactis maestrazgona P. Delforge & A. Gvaudan sp. nova. A detailed diagnosis is given for E. provincialis and E. maestrazgona, another for E. leptochila and E. maestrazgona, as well as a list of 5 localities of E. maestrazgona, prospected in July 2001 and 2004 in Aragon, province of Teruel.
Key-Words: Orchidaceae, genus Epipactis, Epipactis leptochila species group, Epipactis maestrazgona sp. nova, E. provincialis; flora of Spain, Aragon, Teruel.