O. collina means hilly and we can only assume that when it was first described by Banks and Solander from Syria in 1798, it was found in this type of terrain. This species can be found at altitudes up to 1300m but more generally at lower levels and in many types of habitat though always on alkaline substrates and usually in full sun.
It is a very widespread orchid with a range from the Iberian peninsula to the Caucasus but can only really be described as common in Crete, Cyprus and perhaps Malta. There are notable gaps in its distribution, particularly in the Aegean where its presence on one island yet not on the neighbouring island is puzzling.
It has been known for many years that the species has two consecutive but nonetheless distinct flowering periods, the first as early as December and a second which takes it into April. Whether this indicates the existence of two different species is a matter for further study but the prevailing view is that it almost certainly doesn't. O. collina is an unreliable flowerer and its appearance can be sporadic depending on the preceding winter and spring weather conditions.
The species is remarkably unvarying apart from a rare semi-hypochromatic (yet stable) form that has been named as f.leucoglossa. The illustrations are all from Lesbos and date from the first week of April.
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