The Southern Marsh-orchid is tolerant of a wide range of predominantly alkaline habitats, but occasionally it strays into mildly acidic parts of bogs and damp heaths. Best known in the south and often found on riversides and in damp meadows, this orchid also grows in abandoned quarries, on roadside verges and in some old industrial sites; in suitable places it can occur in large numbers. Dactylorhiza praetermissa is extremely variable in appearance and readily hybridises with spotted orchids, causing much confusion during identification. A 'typical' plant would be a robust, thick-stemmed orchid with broad unmarked leaves and relatively large pink-to-purple flowers. It is worth bearing in mind, however, that very small plants can also occur in drier marginal habitats such as chalk grassland. In Britain and Ireland, the Southern Marsh-orchid flowers between mid May and mid July. This species is endemic to Europe, and on the mainland it can be found in Scandinavia, northern France and southwards as far as northern Italy. Dactylorhiza praetermissa Southern Marsh-orchid: identification, distribution, pictures (hardyorchidsociety.org.uk)
It has disappeared from 20% of its historical range. The reduction is almost certainly due to changing agricultural practices and the draining of damp pastures. Southern marsh orchid | The Wildlife Trusts
