Thursday, 9 June 2016

More Marsh Orchids, This Time Southern and Early

Statistics might prove me wrong but by shear volume of visitors, many on large charabangs on day trips, Bourton-on-the-Water in the summer is probably the most popular tourist spot in the northern Cotswolds.  We don't like crowds and as a result we hardly ever go there, but I have now found a very good reason to visit. On the outskirts is a Gloucestershire Wildlife Trust reserve, Greystones Farm which includes the Salmonsbury Meadows SSSI, a wet meadow, on the banks of the meandering River Eye - wonderful on a bright early summer day as today was.  

The meadow has decent populations of Early Marsh Orchid (Dactylorhiza incarnata ssp incarnata - the pale pink form) and also Southern Marsh Orchid (D. praetermissa).   The variability of marsh orchids is curious.

Of the 6 species of Marsh Orchids (Dactylorhiza) in Britain, in my experience 2 show little morphological difference and are unmistakeable (Northern Marsh and Early Marsh - other than the readily recognisable subspecies which are different colour forms), but others such as Common Spotted, and Heath Spotted are very variable both in the colour, spotting on the leaves and marking on the labellum.   They also seem to be catholic about their preferred habitats.  (I commented on the taxonomic issues with Narrow-leaved in an earlier post).   Southern Marsh also seems to show variability;  I saw a deep magenta form on the A34  two weeks ago, and whilst the plants I saw today had a consistent paler hue the labellum shape and the degree of spotting on the leaves were variable.   New Flora of the British Isles ("Stace") has it that the leaves are usually unspotted, with a labellum which is shallowly 3-lobed.  

Between 10 and 20% of the plants at Greystones were spotted.  Are the spotted ones true to the species, or has there been some introgression with Common Spotted, though I found no plants of the latter on the meadow?  The labellum shape was variable, but there seemed to be no correlation between shape and whether or not the leaves were spotted.  The other characteristics matched up to the description in Stace.  Both the spotted and unspotted leaves had a few stomata along the veins of the upper surface of the leaves, consistent with Southern Marsh -Vegetative Key to the British Flora ("Poland"); by contrast Common Spotted only have stomata on the lower surface.   My conclusion therefore that these were in fact all Southern Marsh but the spotting may be due to variability or a small degree of introgression.

Nearby plants included Meadow buttercup, Ribwort plantain, Creeping cinquefoil, Red clover, Fescues, Hard rush, Meadowsweet, Silverweed, Hairy sedge, and Common mouse-ear.

There was plenty of non-botanical interest: inter alia lots of Blue Damselflies, Beautiful Damoiselles and on the Lakes, a close-up of a Great Crested.

I came home via Upper Slaughter; three weeks ago the emerging orchids there were only in leaf.  Using Poland I had them down as a mix of Common Spotted and Southern Marsh.  I went back today to see if I was correct.   Actually not quite.  They all had the appearance of Southern Marsh but about 50% had quite heavily spotted leaves.  I came to the conclusion that even though there were no Common Spotteds around these were  hybrids, D. x grandis (leaves had no stomata on the upper surface, and edge in parts like that of Common Spotted - Poland again).  The flowers had more the shape of Southern Marsh.  Here's an example: 

I will try to give orchids a rest now for a day or too. Orchid non-enthusiasts can rejoice in that it is quite a short season.

Wednesday, 8 June 2016

Moths and Badgers: Close to Home

In the trap on Monday morning were 17 moths, 10 species.   The most spectacular, and new to me, was a Scorched Wing, whose appearance is unmistakeable.

That evening we went badger watching,   When we first moved to Hooky there were two setts within about 2 km of our house, one of which was long established with at least 13 entrances.   The badger population has invreased significantly and now there are at least 4 setts near the original, some of which are now quite large.   We went to one observing from the top of an embankment above the sett.

In the past I have use an infra red lamp with night vision scopes, but it is fiddly, so this time I tested out the simpler approach of using a red lamp.   They did not seem bothered by it, and we watched a family for around 30 minutes.  The camera shutter, even on it's quietest setting caused the most alarm.

An adult emerged at 21.43 and snuffled around in the undergrowth, then nearly 10 minutes later 3 cubs and another adult appeared.  The cubs stayed close to the sett entrance.

In and around the bird feeders we have had a couple of Wood Mice and a Greater Spotted Woodpecker.

Tuesday, 7 June 2016

Botany on the 17th Fairway - Narrow-leaved Marsh Orchids

I was invited today to join a small group monitoring a calcareous fen, a SSSI, a few miles west of Oxford.  It is in the middle of a golf course - the 17th fairway, I think -  and we had permission to survey whilst the course was under maintenance for around 3 hours.   Despite being small, a fragment of former times, it is botanically rich and one of the highlights is a colony of Narrow-leaved Marsh Orchids.   I will purposefully refer to them by the common name because the taxonomy has been a matter of discussion for some time.  

They do look different from other Marsh orchids; the leaves were narrow, around 8mm wide, mostly faintly spotted and keeled.   The flower spike of 29 of the 44 I counted was distinctly one sided, just like the Narrow-leaved marsh orchids I examined on Skye.   The labellum also looked different, some way between that of a Common spotted and Southern marsh.   All were a pale pinkish purple, far less striking than those on Skye.


I am not sure if the taxonomy is fixed.  Skye also has narrow leaved orchids; they used to named Lapland Marsh Orchids (a brilliant name reminding us how far north Skye is, as with other plants found there such as Iceland Purslane), Dactylorhiza lapponica.   These are examples of plants I found there last year in late June.

Molecular comparisons with European populations reclassified these as Dactylorhiza traunsteinerioides along with other scattered northern populations in Britain in, for example, North Wales and North Yorkshire (the plant is never common).   By contrast it has been suggested that the southern populations, those south of a line from the Severn to the Wash, be regarded as a variety (?) of southern marsh orchids, D. praetermissa.   Whether this is now the accepted position, I am not sure; I am not at all sure in fact how taxonomic changes are communicated to the wider world (probably not well, judging from my colleagues - all very competent botanists - over this one example).

The plants I saw today had more similarities with Dactylorhiza traunsteinerioides from elsewhere than D. praetermissa, as can be seen looking at the Oxfordshire and Skye plants, though admittedly there are some differences.   The latter are for example more heavily marked but I believe that it is generally accepted that anthocyanin colouring is heavier the further north one goes.    I made some physical measurements of the plants I saw today and when I have a moment I will compare them with similar measurements on the Skye plants.

So whatever the current taxonomic thinking thankfully the vernacular name works rather well for the plants at both locations.

Inevitably with Marsh Orchids, one plant we found today defied classification, and might well be a hybrid between Common Spotted and Narrow-leaved, with heavier spotting on the leaves consistent with Common spotted, which were coming into flower nearby.   It is probably not worth dwelling over however.