O. heterochila was originally described by Renz and Taubenheim from Mugla, Turkey in 1980 but a similar species was subsequently described by Kretzschmar and Kreutz from Rhodes as O. dodekanensis in 2001. Following research by Paulus and Hirth into the former taxon it was concluded that the two species were in fact synonymous and the name heterochila (meaning "variable lip") was retained.

This was the prevailing view until recently when the opinion was reversed and the two species were again regarded as separate taxons. This view is not at all universally endorsed with many pointing to the fact that they share the same pollinator and that both are reported as very variable with formal descriptions that do not satisfactorily distinguish them. These two species are extremely difficult to differentiate and the authors cannot present this page as authoritative.

O. heterochila was originally thought to be endemic to Rhodes but has subsequently been discovered on other of the Aegean islands, notably Chios, Samos and Lesbos. It's a member of the eastern Mediterranean O. heldreichii group, which although local, can be abundant in a variety of habitats. A key differentiator between O. heterochila and O. dodekanensis is flowering time with the latter declining as the former first appears in mid March. The former also differs in that its lip shows a tendency towards a fuciflorid form whereas the latter generally appears long and thin due to the strongly reflexed lobes. Both species may be differentiated from the similar O. minutula and O. cornutula by the less colourful, drabber speculum.

The pictures are from Rhodes, Samos and Chios, dating from the first week of April.