In addition to the Lesser Butterfly Orchid Platanthera bifolia and the Greater Butterfly Orchid Platanthera chlorantha there is another species of Butterfly Orchid in Central Europe available, that is genetically clearly separate, as investigations by the University of Heidelberg together with the AHO Baden-Württemberg 2021 bis 2025 showed. The BAUM couple from North Rhine-Westphalia had described the species as Platanthera muelleri in 2017. But the existence of this third species in Central Europe was no really new discovery, because HERMANN MÜLLER (1829-1883), after whom they named it, and WILHELM LUDWIG PETERMANN (1806-1855) had already recognized the existence of this third species in the 19th century. PETERMANN had already named it in 1846 as Platanthera pervia in his 'Analytischer Pflanzenschlüssel für botanische Excursionen in der Umgegend von Leipzig' (= analytical plant key for botanical excursions in the surroundings of Leipzig) pages 591/592, according to the spur entrance of this species, which is open visible as in Platanthera chlorantha, too. The two pollinia are not parallel and not as close together as in Platanthera bifolia, nor as inclined and far apart as in Platanthera chlorantha, but take a position in between. This species is widespread in Europe, not only in Northern Germany, the Netherlands and Belgium, but also the long-unexplained 'stable-litter meadow clan' in the southern Upper Rhine Valley belongs to it, as do several other populations in Southern Germany and many populations in the Alps. The southern Italian Platanthera bifolia subsp. osca R.LORENZ, ROMOLINI, V.A.ROMANO & SOCA, described in 2015 and re-combined to Platanthera osca BIAGNOLI, KREUTZ & DE SIMONI in 2022, belongs probably also to this species. Also in Turkey this kind of plants shall be available.