O. langei is a member of the large O. mascula group and was first described by Richter from Madrid, Spain  in 1890. It is named in honour of J. M. C Lange, an eminent Danish botanist of the 19th century . 

It is a western Mediterranean species found predominantly in the Iberian peninsula, extending north to the Pyrenees of southern France and southwards to the middle Atlas of Morocco. O. langei will tolerate a range of conditions but is at its most frequent in mid shade on slightly acidic soils and rarely on the calcareous substrates preferred by many other of its and its mascula group cousins. It's for this reason that colonies can often be found in isolated areas, with very few other orchid species present.

Its close relationship to O. mascula is clear but although broadly similar, there are two key features which convincingly differentiate them. In O. langei the lip of the flower shows a marked kink in the centre, which as with O. lutea, is reminiscent of a knee joint. The second difference is the inflorescence, which is very lax and typically contains half the total number of individual flowers of a comparably sized O. mascula. In the latter species, leaves may be unmarked or heavily spotted with purple blotches whereas in O. langei they are invariably lightly spotted .

Given that O. mascula will happily grow in similar conditions on slightly acidic or siliceous soils it is not at
all uncommon to find them growing side by side and this can present considerable problems with certain
identification, due to hybridization.