It will come as no surprise to regular readers of this blog that I spend rather a lot of time on Holy Island during the spring and summer months. Quite simply, it is one of the finest botanical destinations in the North East. A large part of that appeal lies in its orchids and, while I am more accustomed to visiting in late June to enjoy the island’s helleborines, this year I arrived a little earlier courtesy of a work field trip.

Although the opening days of June are not the best time to see some of Lindisfarne’s more iconic orchids, they are an excellent time to focus on the marsh orchids, Dactylorhiza. In the dune slacks, three species can usually be found in good numbers: Early Marsh-orchid Dactylorhiza incarnata, Common Spotted-orchid Dactylorhiza fuchsii and Northern Marsh-orchid Dactylorhiza purpurella. All three were well represented during our visit.

Of the three, Early Marsh-orchid Dactylorhiza incarnata is arguably the most interesting and is certainly the scarcest locally. Holy Island is one of the best places in the region to appreciate the species’ variation, supporting three distinctive subspecies that correspond rather neatly with different colour forms.

The commonest is Dactylorhiza incarnata subsp. incarnata, with its characteristically pale pink flowers. Somewhat less frequent is Dactylorhiza incarnata subsp. coccinea, whose flowers range from deep pink to rich brick-red. Happily, we encountered both during our wanderings. The third subspecies, Dactylorhiza incarnata subsp. pulchella, proved more elusive. With flowers that can closely resemble those of Northern Marsh-orchid, it remained stubbornly absent from our day list.

The three species are straightforward enough to identify in their typical forms, but as many botanists will know, Dactylorhiza is a notoriously challenging genus owing to the prolific hybridisation that occurs between species. Spotting hybrids is often less a matter of working through a key and more a case of noticing an orchid that looks just a little “off” and investigating further.

By far the commonest hybrid on Holy Island is Dactylorhiza x venusta, the cross between Northern Marsh-orchid and Common Spotted-orchid. Several examples were encountered during our wanderings, typically displaying a pleasing blend of characters from both parents.

The next orchid we encountered on the Snook was considerably more interesting and, indeed, the reason this blog post came into being.

The plant pictured below was a rather handsome pale-pink orchid that immediately struck me as sitting somewhere between Early Marsh-orchid and Common Spotted-orchid. Its colour alone suggested as much, but a closer look revealed several additional clues. The flowers possessed the rather half-hearted spotting one might expect from a plant with D. fuchsii in its parentage, while the lower lip was somewhat swept back, recalling D. incarnata. The leaf tips were slightly hooded in places, and the markings on the labellum took the form of distinct loops concentrated towards the centre of the flower.

Taken individually, none of these features would be especially convincing. Viewed together, however, they painted a rather intriguing picture. The plant appeared to fit the description of Dactylorhiza × kerneriorum, the hybrid between Early Marsh-orchid and Common Spotted-orchid – a scarce orchid that, remarkably, had not been recorded on Holy Island, or indeed anywhere in North Northumberland, since 1985.

Having tentatively convinced myself of the identification, and after sending photographs to a few knowledgeable people for a second opinion, I was delighted when, later that week, my colleague Chris Metherell visited the site to take a look in person. Happily, he agreed with the determination, pointing out several additional intermediate characters, including, importantly, a stomatal arrangement inherited from both parent species.

It seems that, on this occasion at least, my suspicions were correct (hooray!). More importantly, it serves as a useful reminder that taking the time to investigate a slightly unusual plant can sometimes pay off. Interestingly, a glance at the BSBI distribution map suggests that Dactylorhiza × kerneriorum is genuinely scarce across the UK, making the discovery all the more satisfying. Not bad for an orchid that initially caught my attention simply because it looked a little different from its neighbours.