Friday, 13 October 2017

Weeds

I have been looking for archaeophytes, the subject of the upcoming BSBI photographic competition.  Archaeophytes are non-native species, introduced in ancient times, considered to be around 1500.    For obvious reasons many are arable weeds.    The other plant classifications are natives, neophytes - plants introduced after 1500, and increasingly of garden origin - and casuals where a non-native plant, maybe a garden throw-out, hangs around for a year or two then disappears.

Back in the early spring the developer of the estate where I live, in order to eliminate any possibility of flooding from fields to the north, dug a 1.5 metre ditch which was then connected into the estate surface water drainage.  The bare earth has now been colonised by weeds, mostly, if not all archaeophytes, all of which must have been present for several years as seed, because the adjacent fields are laid to pasture.   I counted at least 33 species in the 80 metre length of the ditch, nothing rare as far as I am aware, but it will be interesting to see what happens over time.  The soil is heavy clay.
Ditch

Field Pansy

Spear-leaved Orache

Sun Spurge

Common Poppy

Bristly Oxtongue
On Sunday I ran the moth trap catching over 50 moths of 21 species.   My year to date total is now 146 species.  There were lots of November moths (maybe Pale November moths or Autumnal moths) but treated as an aggregate, because they are difficult to separate.   Moth identification relies in the main or looking for a match in one of the photographic or illustrated guides; for the amateur, unlike plants, there are no keys to work through.  Regularly therefore I have looked at pictures of a very handsome moth, Merveille du Jour (wonder of the day), wishing at some point I might see one.  On Sunday I had five; apparently they feed on ivy which is now in flower.  Sure enough it is one of the most striking moths.  November moths by contrast are just drab.

Merveille du Jour

November Moth
                                         

Friday, 22 September 2017

Greystones Farm: More Fruiting Orchids

Bourton on the Water lies about 17 miles from Hook Norton, over the county border in Gloucestershire.   There is a Gloucestershire Wildlife Trust reserve there - Greystones Farm - which supports quite large numbers of two orchids, Southern Marsh (Dactylorhiza praetermissa) and Early Marsh (Dactylorhiza incarnata ssp. incarnata), in two unimproved wet meadows by the River Eye.

I went looking for fruiting plants, finding a few of both, judged from the leaf width, subtle differences in habitat and the leaf edges.  The seed pods of SMO were shorter and thinner (Average 8.9 x 4.8mm, n=10) than those of EMO (Average 11.5 x 5.5mm n=10).  Despite variability the difference between the two was statistically significant. 

Southern Marsh 

Southern Marsh Leaf


Early Marsh

Early Marsh Leaf
 By contrast size differences between the the seeds of the two species were not different statistically (Av. 0.65 x 0.18 mm vs. Av. 0.71 x 0.18mm).  Examples of each:

Southern Marsh Seed x 100

Early Marsh Seed x100


Back in the village, fungi are starting to appear.   I take this to be Stubble Rosegill (Volvariella gloiocephala), growing under a blackcurrant bush which I have regularly mulched.

Stubble Rosegill


Stubble Rosegill Spores x 630

No moth trapping so far this month.   Overnight showers have been a constant, but the forecast for this weekend looks promising

Wednesday, 13 September 2017

Fruiting Orchids

A nearby meadow which the owner closed to the public earlier this year because dog-walkers were not respecting it, can now be visited again.  


Five orchid species grow in this meadow, though one, Greater Butterfly Orchid, (Platanthera chlorantha) I personally have not seen there.  Yesterday I did find fruits of three, Pyramidal (Anacamptis pyramidalis), Common Spotted (Dactylorhiza fuchsii) and Bee (Ophrys apifera).

Pyramidal seems to set seed then enter the senescence phase quickly.  The seeds had almost all gone.  Common spotted, which flowered at about the same time still had some seed pods, and indeed one plant was still a little green.   Most of the orchid leaves had withered.

   

                              Fruiting Common Spotted Orchids

I made some measurements of the seed pods, because in the senescent state they are difficult to tell apart.  Of course Common Spotted does still have remnants of  bracts amongst the seed pods, but it is a feature that is easily overlooked and can be mistaken for the remains of unpollinated flowers. The pods of Common Spotted got smaller moving up the inflorescence, but this was not true of Pyramidal spikes. It turned out that Pyramidal seed pods were a little longer, but a little thinner than those of Common Spotted. Indeed the pod length to width ratio for the two species was quite different:

Pyramidal                 Pod length to width   0.43±0.19  (n=10)
Common spotted      Pod length to width   0.56±0.12   (n=18)

The difference between the two proved to be statistically significant.   Is this a possible identifier?   I need to collect samples from elsewhere to see if it might be or whether this finding is site specific.

The third orchid typically found in this type of habitat, Chalk Fragrant Orchid, occurs in very small numbers and I could not find any in fruit for comparison, and again I need to look a a little further afield, if I have not left it it too late this year..

It is definitely autumnal now - Blackthorn and Black Bryony in fruit, Ivy in flower.



                                      Sloes



                                           Ivy                          
            

                                     Black Bryony

Black Bryony is toxic due to the presence of calcium oxalate, and seems to be avoided by animals. Estimates suggest that 30 - 40 berries can be fatal to humans; oddly I decided not to test this out.

Thursday, 20 July 2017

July Moths, Relief from Helleborine-spotting

I think I am correct in saying that there are no records of helleborines near Hook Norton and therefore we have been travelling far and wide for much of July tracking down these orchids wherever they might be to get good digital images and a leaf slivver, where allowed, from each species to look at the characteristics microscopically. Lytham in Lancashire and Ainsdale in Merseyside for Dune, Green-flowered, and Marsh Helleborines, Gait Barrows in Cumbria for Dark-red Helleborine (gone over), Chilterns (Homefield Wood and Warburg) for Broad-leaved Helleborine.  Staying in the Chilterns, Narrow-lipped Helleborine has proved elusive, and a plant in bud 10 days previously had already gone over when I visited last Monday, whilst some Violet Helleborine plants have remained stubbornly in bud.
Dune Helleborine (E. dunensis)
Green-flowered Helleborine (E. phyllanthes)

Broad-leaved Helleborine (E. helleborine)

Marsh Helleborine (E. palustris)

Back at home we are really pleased with the garden pond we created just last September.  Stocked with a few native plants, and populated with a few dippings from a pond in a nearby field  we have had three frogs together, and there are growing tadpoles, but  favourite  are the Smooth Newts which have taken up residence.  Now we also have a few young newts - 'newtlets' if  that is the correct word.  A minor disappointment is that we have not had any damselflies or dragonflies yet however.



Almost as a distraction I have run the moth trap overnight, twice in the month, both nights being warm and still.  The counts were large, 151 moths of 50 species at the beginning of the month, and this week even more, 248 moths of 61 species.  Even then there were quite a few escapees when I came to inspect, especially Yellow Underwings.  The total species count for the year to date is now 119, including the more challenging micromoth category.  A few chosen almost at random.

Burnished Brass

Brown-line Bright-eye

Dark-barred Twin-spot Carpet

Ruby Tiger

Wednesday, 5 July 2017

Greater Butterfly Orchids in the Chilterns - Fruiting

Down in the Chilterns, a farmer with a strong interest in wildlife has turned over some of his less productive arable fields to wild flower hay meadows.   He is quite passionate about orchids, and in an adjoining woodland there is a thriving population of Greater butterfly orchids (Platanthera chlorantha), which he found a few years ago.   The numbers have increased over those years with a modest degree of management.


I have been fortunate to be allowed free rein on starting a study of the plants, which hopefully will lead to a long term demographic study. The plants are in two patches around 75 yards apart, separated by a forest track, and the farmer has enclosed each group with a four foot fence to keep out deer (conveniently the North and South enclosures)  The canopy, of hazel and beech, shades the plants to quite a degree and we made some measures of the light levels.  Bramble and Dog's mercury surround the orchids.
Plant #89

Plant #89 in Fruit

Plant #84

Plant #84 in Fruit
So far we have marked just about all the plants - flowering and non-flowering - with a total of 343 plants.   We measured the leaf width of the non-flowering plants, and for those that flowered we measured the height, leaf width, spur length, and number of flowers.   Last week we went back to count the number of fruits on  the plants that flowered.  The fruiting success was 31.7% in the Southern enclosure and 28.0% in the Northern enclosure, though I don't think the difference is statistically significant, because the fruiting success of individual plants ranged from zero to in one case, 100%.    By comparison the 5-year average on Skye was 28.6%, plants out in the open in a quite different environment.

Analysis will follow, but an early observation is that the fruiting success of the earliest flowering plants was much the same as those that flowered a couple of weeks later.


Monday, 26 June 2017

Post-flowering fate of Man Orchids at Ufton Fields.

Ufton Fields, a Warwickshire Wildlife Trust reserve, has a small population of Man Orchids (Orchis anthropophora).  In late May we counted 5 flowering spikes among the 25 cages marking plants that are, or have at one time been seen, there. In addition 2 more plants were in bud.  There were no plants outside the cages.  Excluding one of the 5, which was spindly and frail the average height of a flower spike was 26cm with 27 flowers on average.
Man Orchid in Fruit


Ufton Meadows - Man Orchid Cages

A frail plant that simply withered


I went back this morning to see the fate of these plants.  Without the cages they would have been impossible to find in the developed sward.   Lady's bedstraw and St John's-wort were everywhere.

The two plants that were in bud did not develop and had died off, as had the frail plant.   This left 4 spikes which had developed fruits with a total of 34 seed pods. Including the frail plant there were originally 123 flowers, so the fruiting success was 28%.  The fruiting success of individual plants varied from 0 (the frail plant) to 42%.

Last week we carried out a similar exercise at Bernwood Meadows, but not very successfully.   In early May we counted the flowers on 174 flowering spikes of Green-winged Orchids (Anacamptis morio) which averaged 6.8 flowers per spike in a survey area we created.   We went back to count fruits, at lunchtime on one of the hottest days of the year last week.   This is not an excuse for the fact that we could only find 31 of the original 174 flowering plants.  Those had an averages of 3 seed pods and 7.9 flowers.  The apparent fruiting success was therefore 38%.   But what of the plants that we could not find, which appear to be those with fewer flowers?  The total number of flowers we counted was 1193 and the total seed pods we found was 93; on this measure the fruiting success was only 8%.   The survey at Ufton Fields shows that unless individual plants can be identified in flower then again in fruit, assessment of the fruiting success is extremely difficult.
Bernwood Meadows
Fruiting Green-winged Orchid


Monday, 5 June 2017

Fruiting of Early Purple Orchids at Westwell Gorse

The Early purple orchids (Orchis mascula) are now in fruit at Westwell Gorse. 


In flower 4 May
In fruit 2 June

In flower 4 May
In fruit 2 June (top chewed)
In early May we measured the height and counted the number of flowers on 83 plants in a survey area we designated.  We went back on Friday to count the number of seed pods in order to estimate the fruiting success.  We found 63 plants; once the sward is higher it is  challenging to find just the fruiting plants.   For each we counted both the number of seed pods and the number of dead flowers that had not fruited.   From this we estimated the fruiting success at 36%, but it needs correcting.   In May the average number of flowers per plant was 9.8, whereas last Friday we got a lower figure of  8.6.   Either we missed some of the larger plants with more flowers, or more likely some of the buds that we originally counted as flowers did not develop, but just fell away.  If we apply an adjustment of 8.6/9.8 for the number of flowers then the fruiting success falls to 31%, which by coincidence is the same figure as in 2016.

The figure compares with references given for some German studies by Claessens and Kleynen in The Flower of the European Orchid ranging from 7 to 67% with an average of 34%.  Results from Sweden quoted in the same text were lower.   A Norfolk study (Hardy Orchid Society: April 2013) got a much higher result, 84%.  That looks atypical.

The range across individual plants was from zero to uncommonly 100%, with no real pattern.   The chart below plots Fruiting success (Y-axis) against Number of flowers per individual plant (X-axis)


It was noticeable that flowers at the top of the spike - those flowering later - were less likely to be pollinated, though we made no attempt to quantify the effect.

Pyramidal orchids were just coming in to flower, whilst there were 10 plants of Purple Milk Vetch, which is on the Red Data List.
Pyramidal Orchid

Purple Milk Vetch