The main flush of Dactylorhiza orchids has appeared. These are always at their best when the lowest rank of flowers has just newly opened.
For years, there has been a huge debate about the number of species and descriptions of the species and hybridisation. It is known that they hybridise and back-cross, so I suggest that most specimens are an intermediate 'hybrid' amongst 3 key 'species' in our location: Common Spotted Orchid (CSO), Heath Spotted Orchid (HSO) and Northern Marsh Orchid (NMO). Given that these 'species' hybridise so regularly, I can't see any uncorrupted ones being possible, so I rather think that we are taking a few distinguishing characteristics and lumping individuals into one bucket or another, depending on what we see.
This one shows the main features of 'CSO'...tall spike, three very clear lobes to the base of the flower, very little frilling:
This one shows more influence of 'HSO', with much frillier lips and a slightly shorter spike.
This would appear to have some NMO influence...much darker markings and a still shorter spike:
I'll leave the next few to your own imagination.
The lower left flower in this specimen shows the nectar hole being clearly indicated by the purple lines, which act as a guide for insects. The hole suggests that these species need a long-tongued insect like a butterfly or bee to pollinate them. Pollination is carried out via the pair of brown pollinia which attach pollen to the back of the pollinating insect.
This last one, however, shows a nice feature. The flowers form 'upside down', and only then do they rotate to their final position.
That last one would be pure 'CSO' if it wasn't for the (very) short spike.
Gill mentioned in her comments that the inverted flower looks more developed than usual. This is true. A close look reveals that the 'lower' lip has developed too quickly and has jammed against the flower above it. This combination of features will prevent the flower from passing on any pollen, so this is the end of the line for that combination.