O. ferrum-equinum var. parnassica was first described by Vierhapper from central Greece in 1920 and its name refers to the site of its discovery in the foothills of Mount Parnassus near Delphi.

The nominate species, O. ferrum-equinum is a widespread eastern Mediterranean Ophrys of which several varieties have been formally described and named, though by no means all of them have been accepted as valid, often being regarded as plants which simply fall into the type species range of natural variation. O. ferrum-equinum var. parnassica is however a generally more distinctive taxon, although one that is hugely variable and which is difficult to definitively describe.

This variety has a localized but wide distribution in the eastern Mediterranean and probably may be encountered anywhere within the range of the nominate species. O. ferrum-equinum readily hybridizes with nearby Ophrys species and this factor coupled with its natural variability sometimes make identification problematic. O. ferrum-equinum var. parnassica can easily be confused with hybrid plants and the photos included here could easily fall into this category. Pictures 1 and 4 are however most representative of the taxon. Typically, O. ferrum-equinum var. parnassica is most clearly recognized by its pale green, sometimes white sepals and its long, pale orange petals. The lip tends to be  dark, even black and the speculum can range from the usual horseshoe to extremely reduced droplets.

The illustrations date from the first week of April and come from Kos, Chios and the Peloponnese.