Saturday, 30 April 2016

Golden Saxifrages at Whichford Wood

Around 5 miles away and over the county border, Whichford Wood, is the nearest woodland to Hook Norton, other than a few coverts and the linear woodland which marks the course of the former Banbury to Cheltenham railway.  

We went there to see the impressive display of bluebells but also to look for Early purple orchids and Alternate-leaved golden saxifrage (Chrysosplenium alternifolium), which is recorded there and at only one other locality in Warwickshire.  It is quite rare in the south Midlands and South-east more generally. Gratifyingly we found a few patches in amongst its sibling, Opposite-leaved Golden saxifrage (Chrysosplenium oppositifolium), which was far more widespread in the wood. Alternate is more robust, more imposing because the yellow petal-free flowers are larger.   Both grow in damp edges of the woodland.

Alternate-leaved golden saxifrage
Alternate-leaved golden saxifrage
Alternate-lvd g.s (top) compared to Opposite-lvd g.s. (bottom)
No orchids but a list of 50 or so plants in total despite the tree and grass count being cursory, including inter alia Town Hall Clock (Adoxa moschatellina), Yellow Archangel (Lamiastrum galeobdolon), Wood-sorrell (Oxalis acetosella) and of course Wood Anemone (Anemone nemorosa).  The bluebells alone were certainly worth the trip, but we also saw our first cuckoo of the year, at least 20 roe deer, 4 jays, and a hare, so not bad.
Whichford Wood

Town-hall Clock
Roe Deer
Yellow Archangel

Whichford Wood

Tuesday, 26 April 2016

Early Purple Orchids

I think orchids are just the best!

I went over to Westwell Gorse this morning and as expected Early purple orchids (Orchis mascula) were at last just coming into flower.   One of the earliest orchids to emerge, records have been posted on Facebook of plants in flower starting on the Isle of White on 13 April, then Kent and Sussex, South Wales and so on.  At Westwell there are at least 50 plants at a guess, all on a dryish area on the edge of scrub, rather than in a more wooded area nearby.

The plant is widespread throughout the UK; Stace suggests a preference for neutral to basic soils, out in the open up north, more shaded down south, more common in ancient woodland, so the Westwell situation is a little surprising.   Elsewhere in Oxfordshire I have seen plants at Foxholes in damp woodland whereas on Skye it was not uncommon to find it on ungrazed basalt ledges on mountain slopes, buffeted by winds, or on the limestone pavement of Ben Suardal in the south of the island.   It is though hard to see a pattern in the distribution and be able to predict where it might occur. 

It has virtually no hybrids with  other UK orchids.  It is commonest member of the Orchis genus in the UK.  There is a distributional overlap, but Stace et al in their Hybrid Flora of the British Isles give only one record for the hybrid with the Green-winged orchid, Anacamptis morio (recently reclassified from Orchis morio), and there seems to be no hybrid with Man orchid.   Given the libertine nature of several orchid genera this seems surprising.

I found this orchid just about the easiest to recognise from just the leaves.    It has a definite rosette - some of the smaller plants I looked at this morning had as few as 4 leaves all at right angles, but more robust plants had more basal leaves, essentially in a two tiered rosette, radiating out as if the spokes of a wheel.   Stem leaves are sheathing. The leaf spots are larger and more blotchy than those of Common spotted orchids; the leaf edge is described by Poland and Clement as crenulate.

Friday, 22 April 2016

The National Plant Monitoring Scheme - A Chore

The National Plant Monitoring Scheme was put together by BSBI and Plantlife to survey designated locations on at least an annual basis.   On a pseudo random basis 1 km squares have been selected throughout the country and volunteers invited to adopt one (or more) of those squares close to home, with a commitment to select 5 5x5m plots 25m linear strips at targeted spots within the square, then survey those plots twice annually.   

It was designed, I think, as a citizen science project, but I think few of my fellow citizens who are not botanists will stay the course.   The documentation is complex, you need a gps device, and it is time consuming (and if the square is dull, a chore).

I did the first of my two surveys today in my square, which is on the western edge of Chipping Norton.  The NPMS was not designed with such a square in mind; most of the square is either arable (with not even a hint of a wild plant) or difficult to access, with scraps of woodland given over to pheasant shooting.    The square is also encroached by urbanisation.   The most interesting scrap of land was what might best be described as set aside, though more probably it is lying fallow awaiting the developers - the kind of scruffy habitat that Mick Crawley, the author of British Aliens would find of some interest.  It does not appear as a habitat in the NPMS guidance.   

I understand that others in north Oxfordshire have struggled for the same reason as me.   Comment about what is at each of the targets within the square might have added an extra dimension to the scheme, giving a snapshot of what the countryside really is like, but it has not been asked for.   A pity.

With some difficulty I did manage to mark out 4 5x5m plots and one 25m linear hedgerow, fairly close to the targets,  recording all the plants in flower and some where I was 100% certain of the leaf id.  Still the total species from the square was a very disappointing 52. Now to fathom out how to send in my data.

If the NPMS survey was the lowlight of the week there were some real highlights.   On Tuesday my wife and I went along to Cothill Fen, just west of Oxford visiting Dry Sandford Pit, Parsonage Moor and Hitchcopse Wood.   Below are some of the pictures from the trip.    
Towards the end of our walk, my wife confirmed that she is a witch with an ability to commune with nature; getting a little worn out from plant hunting her comment was 'that we needed something small and furry'.  Immediately up popped a stoat, wandering nonchalantly towards us, and almost at the same time a brown long eared bat made slow glides past us stopping occasionally on a tree or in the undergrowth.  This is the first time I have ever seen a bat in full daylight.

Dry Sandford Pit
Dry Sandford Pit
Marsh Marigolds
Woodland Flowers in Hitchcopse Wood
Brown Long-eared Bat

Then on Wednesday I went on  BSBI recording mission, organised by Sue, the Vice county Recorder, to Cornbury where access is usually very limited.  In 2 1km squares we recorded around 160 species; mostly in established woodland but with a quarry and a marsh.  Standout for me was an adder basking on the bole of a tree, so deceptive that I was no more than 2 feet away, yet only realised what it was when it wriggled away.   There were three orchids in leaf, common spotted, common twayblade but I could not be certain of a third so it will be back to Cornbury in June!  

Common Twayblade Leaves 
Wild Strawberry

Yesterday I took another look at some pyramidal orchid leaves.   The key in Poland works to a point, but discrimination against Chalk fragrant orchids falls down when the plants are young, because reliance is placed on the persistence of the leaves - leaves of pyramidal begin to die down at flowering.   

Pyramidal orchid leaves
Pyramidal orchid leaves with scale

Monday, 18 April 2016

Orchid Hunt and the Irresistible Pasque Flower

There is so much to see and so little time.

Orchids when they first appear can be tricky to differentiate one species from another.   Looking at Facebook postings most are just guesswork.  A similar problem occurs when the plants have flowered but there are differences in the size and shape of seeds and the seedpods.  Over the last few days I went to several locations with reliable orchid populations to see how useful the keys in Poland and Clement's vegetative key to British plants were, recognising that leaf width and length, a useful feature when plants are fully developed, was irrelevant.  I am growing very familiar with keys JG to JL - whether stomata occured on upper as well as lower leaf surfaces, whether crenulate (toothy) or entire leaf edges, hooded leaf tip, and so on.    I am also keen to see if there are other helpful characteristics that are not in the keys but which might be useful.    With some species the keys worked, but others were more troublesome, where the keys did not reliably fit, and there may be other characteristics that could aid identification.   I will have to return to confirm my tentative conclusions in 4 or 5 weeks time.

At Lea Valley, a calcareous fen valley near the centre of the city, and a famous botanical locality, I found leaves of Common spotted orchid (Dactylorhiza fuchsii) - leaves spotted, no stomata above, and a distinctive purple, crenulate (= minute round toothed) edge.

Lea Valley

Common Spotted Orchid Leaves
Common Spotted Orchid Leaf - Upper Surface and Edge

Common Spotted Orchid Leaf - Upper Surface and Edge
On Friday I went to Ardley Quarry, a BBOWT reserve around 15 miles from Hook Norton, finding Common spotted orchids again, but also what I think, and rather hope, were Southern marsh orchids (Dactylorhiza praetermissa) and a few Common twayblade (Neottia ovata)   I will have to check these next month when they flower - a test for the accuracy of GPS.   Southern and northern marsh orchids look quite different and as the common names suggest one is found in southern Britain, the other in the north.  These are the BSBI distribution maps for the two species (all records).  The overlap is very limited which begs the question as to why there is a clear geographical preference, one to the other.   It is not explained by geology, could it be the amount of daylight?

 Southern Marsh All Records         Northern Marsh All Records

Recent observations suggest that Southern marsh orchid is pushing northwards with a few records from Cumbria since 2000.   As an aside there are a scattering of records for D. praetermissa from the Skye and Raasay  pre 1960; surely these are incorrect and might have been mistaken for hybrids of D. purpurella x D. maculata.

Ardley Quarry had other interest; 4 violet species which could be compared directly - Common and Early Dog-violet, Hairy Violet and a small patch of Sweet Violet, and some Stinking Hellebore (Helleborus foetidus).

Yesterday it was the BBOWT reserve at Westwell Gorse for Early purple orchids (Orchis mascula) and Common twayblade.   Though both  Early purple and Common spotted have variable, purple spotted leaves, the former are shinier and there is a clear leaf rosette, but not the purple crenulate leaf edge.

Leaves - Early Purple Orchid

Early Purple Orchid Leaf - Lower Surface and Edge

Westwell Gorse
Early Purple Orchid Leaf - Upper Surface and Tip

Some of the Early purple orchids were in bud, yet in some more southern locations there are reports of them already in flower.  I had expected them to be in the shade and was slightly surprised therefore that at Westwell they are out in the open.

Westwell Gorse is not too far from Barnsley Warren, Gloucestershire Wildlife Trust's Pasque flower reserve, and the temptation to see the pant proved too much.  Though I found less than 20 plants, in the shorter, rabbit grazed sward, avoiding the coarsest grassed areas, it was well worth the diversion.  In my view the showier the better and very few can beat Pasque flowers; not for me the connoisseur 'delights' of grasses and sedges, bring on the showy flowers.

On a Celandine at Westwell Gorse, I found a fly which until I looked carefully. I would never imagined was a hoverfly.   Glossy black, and in close-up looking like a boxer's sparring partner, helmeted and ready to go, I have it down as Cheilosia vernalis, though there are several closely related species and I might be wrong.   Whilst it looks threatening and intimidating, bear in mind that it is only 5mm long.

I had the moth trap out in the garden last night.  Quite cold, only 2 species turned up, an Early Grey and a Hebrew Character.
Early Grey
Hebrew Character

Sunday, 10 April 2016

Survey of Grape Hyacinth (Muscari neglectum) with Celebrity Endorsement

Another week, another Wychwood Flora Group survey, this time extending an already long time-series of the number of flowering plants of Grape Hyacinth (Muscari neglectum) at 4 locations in and around Chadlington, which is the other side of Chipping Norton.

There were hundreds on the village green.  If there was a habitat preference it was for areas where there was less competition from grasses and more aggressive plants, because the Muscari were both out in the open, accompanied by cowslips, but also under bushes in shade.   There is a widely held view that they prefer a south-facing, dry corner but looking closely today I don't think that is necessarily the case.    

Muscari neglectum
Village Green, Chadlington
Edge of Arable Field, Chadlington
We started out as a survey party of 8, but were joined at the final site by no less than Jeremy Clarkson, because we were after all on his land (but with permission to be there).  There was  no sign of shotguns being readied to dispense with trespassers or ploughs prepared to erase any trace of the Muscari growing there as might be consistent with the Top Gear presenter, but it is well known that the TV persona is far removed from what the private individual is like, and we found Jeremy interested in the rare species he had on his land with perhaps a little pride.   Indeed his land management is very sympathetic to wildlife - a nearby meadow had lots of cowslips, and skylarks. Although greater public access would be terrific it would end up being overrun by dog walkers,  the uncontrolled pooch I encountered elsewhere today was called Oscar.    WFG are keen to return later in the summer to carry out a full survey of the plants there later in the year.  Inter alia  I suspect that there will be 3 or 4 orchid species. 

I almost forgot; unlike most TV personalities he is actually a lot taller than he looks on the screen!

I do wonder if at one time Muscari neglectum was found in some of the arable fields around Hook Norton, because quite a few of the gardens in the village, especially the older cottages, have the plant. Druce's Flora of Oxfordshire has a record from 1881 at Adderbury and the Chadlington site, which are not too far away.

There are also some possible hybrids of  M. neglectum and the common garden Grape hyacinth M. armeniacum.    I found, though, on a very brief review, an interesting PhD thesis by Ylva Heed which concludes that M. neglectum has several ploidal levels such that species boundaries are hard to define (   I will collect examples over the next few days of the pure plants and intermediates in and around the village.  Not that I will be able to make any contribution to science in this molecular age.

Sunday, 3 April 2016

Whitehill Wood - Gagea lutea (2)

The Wychwood Flora Group and its predecessors have been making an annual survey of a population of Yellow Star-of-Bethlehem (Gagea lutea) for over 20 years in Whitehill Wood.  The wood is near to North Leigh and the plants grow close to the bank of the River Evenlode under mature hazel. They are also precariously close to a well used footpath.   I have participated - ie been there as a bystander whilst Ken and Brenda do the work - several times in previous years and it is something to look forward to as it seems to me to mark the start of spring.  It always seems to be sunny on the chosen day which helps.

Whitehill Wood
River Evenlode
The survey counts the number of plants in flower, never more than around 25, despite a much larger number of non-flowering plants, and quite variable year by year.  Indeed I have borrowed the data to see if there is any correlation with climate statistics to explain the variability, when I have a quiet moment.   

Yellow Star-of Bethlehem (Gagea lutea)
It takes a little time to tune into Gagea spotting because when not in flower Gagea can easily be mistaken for bluebells. But the leaves are different; although a similar width, Gagea leaves are a more yellowy green, more strongly keeled and have three veins on the underside compared to just one for a bluebell leaf.

Yellow Star-of-Bethlehem Leaf Underside
Bluebell Leaf Underside
Wood anemone and Early Dog-violets were in flower, but not another regular there, Toothwort, a parasite of Hazel for which our visit was perhaps a couple of weeks too early.

Early Dog-violet (Viola riechenbachiana)

Wood Anemone (Anemone nemorosa)
Plenty of deer tracks, both muntjac and roe (and the obvious question is whether they eat Gagea plants and reduce the number of flowers) and one of the party saw a water vole,  I got quite excited when I found what I hoped were a cache of hazel nuts eaten by dormice.   That would have been a find, but disappointingly under magnification they had the characteristic gnaw marks of wood mice rather than the smooth lathe like inner surface caused by dormice.
Hazelnuts Chewed by Wood Mice
Finally near the wood some sadness; a road kill of what I am fairly certain was a polecat (dark feet, white around the face in the right places).  Not for the squeamish but I am looking for agreement or otherwise.  Polecats have been slowly spreading east from Wales across England but I don't think there have been too many sightings in Oxfordshire.    The Vincent Wildlife Trust did a survey in 2014/15 but I am not aware of any results from it yet.