Often hybridizes with :

• Common Spotted-Orchid (Dactylorhiza fuchsii) to produce Dactylorhiza × grandis likely the commonest hybrid in Southern Britain.
• Heath Spotted-Orchid (Dactylorhiza maculata) to produce Dactylorhiza × hallii much rarer than D. × grandis.
• (Early Marsh-Orchid) (Dactylorhiza incarnata) to produce Dactylorhiza × wintoni which is scattered from Southern Britain up into South and North Lancashire.
• (Northern Marsh-Orchid) (Dactylorhiza purpurella) to produce Dactylorhiza × insignis seen in Cardiganshire and Merioneth, but probably occurs elsewhere where the two parents overlap.
• (Narrow-leaved Marsh-Orchid) (Dactylorhiza traunsteinerioides) to produce a hybrid lacking an alias. Found only in West Norfolk and Cambs.
• Chalk Fragrant-Orchid (Gymnadenia conopsea) to produce the inter-genera hybrid X Dactylodenia heinzeliana which is scattered throughout the UK.

It is thought that the sub-species junialis should rather be considered as a variety junialis, which occurs not infrequently in south-west England, could be a hybrid between Southern Marsh-Orchid and Common Spotted-Orchid, but the jury is still out pending more work on their true identity. They have the moniker Leopard Orchid on account of the spots or stripes on their leaves.

The stems are hollow which can be tested by a gentle squeeze.