Dactylorhiza majalis (UK)

Further to my comments on Dactylorhiza in Kashmir/ Ladakh, then H.P./Uttarakhand and Bhutan/Nepal, I consider it worth sharing some further information on the genus in the UK. My objective is to show the complexities and challenges involved in identifying species within

Dactylorhiza and Gymnadenia.   Sorry, some genera are NOT simple.

The Botanical Society of Britain & Ireland has a Panel of Referees and Specialists willing to be sent dried or fresh specimens or photos of particular genera or families which are known to be ‘difficult’ and often beyond the capabilities/expertise of most members to RELIABLY identify. This is helpful, although I have only availed myself of this service on the one occasion to-date.

I mostly avoid tackling such difficult genera – not because I could not but realise the amount of effort which would be required to familiarise myself with ALL of such ‘difficult’ genera, so where does one start (or stop).

My time is better spent ATTEMPTING to identify Himalayan flora.

For Dactylorhiza and Gymnadenia (and all Orchidaceae except Epipactis, which has a separate Referee) there are two Referees, one specialising in Southern UK, the other Northern UK).

The MINIMUM these referees require for them to ATTEMPT to ‘determine’ the plants are images of whole plants plus close-up of inflorescence, ideally with a ruler to give scale.  These photos should be supported by notes on size, locality, habitat and other species of the same genus found nearby – this information being essential if hybridisation is suspected. 

Supporting specimens are advisable for especially problematic plants. ‘Fresh’ specimens are the best (though this requires the availability of the Referee to inspect the specimen promptly having been posted by the quickest means possible). A single, fully opened flower and the subtending bract in an airtight vial or similar plus the longest sheathing leaf are sufficient. ‘Pickled’ flowers supported by colour notes are less

satisfactory.  It is not necessary nor appropriate to remove/dig-up the whole plant.  Living material cannot be legally collected from species protected by Schedule 8 of the UK Wildlife & Countryside Act and it is illegal to uproot any wild plant without the landowners permission.

I am currently helping towards the BSBI’s Atlas 2020.   The whole of Britain and Ireland is divided up into 2km x 2km Tetrads with the objective to record as many (ideally ALL) the species found in each tetrad. Notes about the correct identification of some of the difficult and under-recorded taxa are provided.  For Dactylorhiza it states that material which is not obviously identifiable according to Stace’s ‘New Flora of the British Isles’, should be submitted to local experts or national referees.  Photographs of whole plants and key features, supported by notes on locality, size, habitat etc. are accepted.

As for Gymnadenia – the three species known are under-recorded.  Notes (in the form of a ‘crib’) are available to help distinguish between the species.

Stace describes Dactylorhiza in Britain & Ireland as a very difficult genus owing to ready hybridisation between any of the species with a complex pattern of variation within most species. Considerable differences between populations are often evident.

There is much disagreement as to species limits.  He considers that except for ‘typical’ material it is often not possible to identify single specimens!   He advises that before using the key he has come up with, the whole population should be surveyed and the “means” of 5-20 non-extreme plants calculated!

He warns that of the 8 species known in Britain & Ireland, 2 are diploid, the others tetraploid.  Hybrids within a ploidy are highly fertile.  Hybrids between ploidy levels are usually though not always sterile.  Even in the case of triploid hybrids, back-crossing and introgression can occur…..

A few years ago I visited Wales with a fellow botanist who had been a member of the University of Southampton Ladakh Expedition back in 1980.  We were able to photograph some wonderful orchids growing on the coast near a sand-dune.

I remain uncertain as to the full identity of these orchids.   My understanding is that most of the country’s orchid specialists have visited these colonies and there may well be a degree of hybridisation involved.  Shall leave it to the orchid taxonomists the decide (debate) as to what precisely is present. I am happy to simply admire the beauty of such orchids. 

In the mean-time, I attach some images of those wonderful orchids we saw in Wales (probably some sort of hybrids). 

The majority (nos. 1-8) are of what is probably, in the main, ‘The Western Marsh Orchid) Dactylorhiza majalis; the remainder (nos. 9-11) are probably of Dactylorhiza incarnata. IF there are an experts out there who can improve upon these idents or correct them, please let me know but for most ‘mortals’, I hope you just savour their beauty – long may such colonies remain.

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