Northern Marsh Orchid hybrids

It may, just, still feel like summer down in mainland Britain at the moment, though the signs of the changing seasons are there, if you look a little closer in the hedgerows – blackberries and sloes are starting to sweetly and sourly tempt. They’re a reminder to me that I should keep an eye open for crowberries here in Shetland – though, as gathering enough of these tiny berries to be useful in the kitchen takes an achingly long time, I should perhaps just leave them for the local birds. Judging by the purple spatters they leave on the windows of my island home, crowberries are a popular seasonal treat for the local Starlings.

The flowering season here is definitely drawing to a close, particularly for my favourites, the orchids. Bog Orchids are the last to flower in Shetland and they’re presently waning while, on the south coast of England, the Autumn Lady’s-tresses are well under way. I’ll soon have a grandstand seat for one of Britain’s great wildlife spectacles – the migration season for birds across the Northern Hemisphere is slowly beginning, and before long Shetland will be inundated with birds from nearby Scandinavia and much, much further afield too – lost birds will make landfall here from Siberia and North America.

All of this is still to come. There’s a sense of unhappening here, the stretching void before a clock strikes the hour. I’ll be charting the unfolding migration for Rare Bird Alert in the coming weeks but, for now, I have a brief chance to be indulgent and look once more at orchids and, in particular, one of my favourites.

Northern Marsh Orchids (image right & above) are fairly common here in Shetland, and can be found across much of Scotland and northern England too. Being Dactylorhizas, they’re promiscuous and readily hybridise with their near relatives – so I thought now would be an opportunity to bring together in one place a handful of images of the various hybrid combinations I’ve encountered lately.

Their hybrid offspring (Dactylorhiza x formosa) with Heath Spotted Orchids (image left) are ubiquitous in Shetland – so commonplace, in fact, that I realise I rarely pause to take a photo of those I find…

Where they meet Common Spotted Orchids they’ll hybridise just as readily with that species too – though the offspring of this combination (Dactylorhiza x venusta) vary between different areas – those in the Hebrides (image right) being a much more intensely coloured affair, owing I think to the Common Spotted parent belonging to a darker, richly marked local subspecies known as hebridensis. Those hybrids found on the opposite coast of Britain, in the dune slacks of Lindisfarne (image below), have paler though still hardly insipid flowers.

So far, so good – much rarer, however, are hybrids with Early Marsh Orchid and Frog Orchid. I found my first example of the former (Dactylorhiza x latirella) here in Shetland earlier in the summer (image below) – an identification I cautiously made for myself at the time, but was pleased recently to receive confirmation from the Botanical Society of Britain Ireland’s (BSBI) orchid referee, Dr Ian Denholm, that I’d got this right.

The latter hybrid, that of Northern Marsh Orchid paired with Frog Orchid, is at least as rare as the former. Frog Orchids, at first glance, don’t look much like the rest of the Dactylorhiza clan, but in recent years we’ve learned they are, in fact, primitive Dactys after all. We should, perhaps, have suspected as much – for their hybrids with Common Spotted Orchid have been well-known if never common for many years. Encountered even less frequently are their hybrids with Northern Marsh Orchid (X Dactyloglossum viridellum), but last year I found two such hybrids – their flowers elongated and subtly isabelline, betraying the Frog Orchid influence (image below).

For anyone who’d like to delve a little deeper into the myriad hybrid permutations of Northern Marsh Orchids and their close Dactylorhiza relatives, there’s a handy website* that provides not only a chart of the possibilities, but also links to the BSBI distribution maps for each – a chance, perhaps, in the long months of autumn and winter ahead for the orchid hunter to plan next year’s expeditions.

* though note,  it still refers to Frog Orchid as belonging to Coeloglossum and, hence, its hybrids with Dactylorhiza as inter-generic, hence the awkward Latin name for them. The incorporation of Frog Orchid into the Dactylorhiza is neither universally popular, nor wholly accepted…

 

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