This taxon has variously been considered a variety or subspecies of O. ferrum-equinum and more recently following studies in Turkey and the Aegean island of Samos, as a full species in its own right. The uncertainty has however (albeit unsatisfactorily) been put to rest and labiosa has settled into existence as a variety. This determination seems appropriate as it most frequently appears amongst colonies of the nominate race and where this occurs, intermediates between type and variety labiosa are not uncommon. The previously mentioned studies however, reveal that O. ferrum-equinum var. labiosa exists in pure populations (exclusively so on Samos) and exhibit a phenology that is noticeably different. There is therefore a significant body of opinion supporting the maintainence of full species status. 

Lip markings are variable but typically exhibit a basic horseshoe shaped speculum that is seldom elaborate and often just two vertically parallel lines. Photo 9 is particularly interesting in that the lining of the speculum continues up to the basal field and around the neck of the stigmatic cavity, this being a characteristic more commonly noted in O. spruneri. The key identification feature is the strongly convex lip and flared margins which gives it the face-on appearance of a frilled black olive !

It's range was once thought to be limited to Anatolia and the Aegean islands but is now known to be fairly widespread, albeit less common in mainland Greece. O. ferrum -equinum var.labiosa is thought to flower marginally earlier than O. ferrum-equinum, the examples illustrated here date from the first week of April, coming from Chios, Cephalonia and Mount Hymettus near Athens.