Friday, 3 November 2017

Moths - Annual Review

I had the moth trap out last night, which was dry but not especially cold, and managed just the one moth, a December moth.   There are probably few, if any new species that I might emerge before the year end, so I don't think I will put the trap out again until next year.   Thus the species count for the year is a convenient 150; there may be a few mis- identifications, for example the rustics, and I have taken aggregates for the 3 species closely related to November moths, which need genitalia examination to correctly identify.  (A step too far!) 

December moth
The following plot shows the number of species first seen in a particular month:


Comparing the species list with my records for Skye, 500 miles or so further north with mild wet winters and cool wet summer, of the 150 species, I had seen 56 (37%)  before on Skye, and as might be expected the moths that emerge down south in spring are more likely to be on both lists than those which appear in summer as the weather warms up.    


The moth that turned up in more months than any other was Flame shoulder which appeared in 6 of the 9 months, though only in small numbers, whereas the highest number caught was the setaceous Hebrew character.
Flame shoulder

Setaceous hebrew character

Tuesday, 24 October 2017

Orchid Seeds and Seed Pods - A Diagnostic?

I have collected seed pod data for 33 orchids, measuring length and width, partly derived from photographs when they are in fruit and adding a scale to the photograph. There is variability; for some species, but not all, the pod size decreases up the inflorescence.  Nevertheless the ratio between length and width is more consistent for each species, and the number may be characteristic of that species.   I was able to use the ratio to discriminate between for instance common spotted orchid and chalk fragrant orchid.  The results overall show that the ratio can help discriminate between species, not necessarily conclusively but as an example Chalk fragrant orchid (Gymnadenia conopsea) and Pyramidal orchid (Anacamptis pyramidalis) which have similar leaf shapes have quite different values. I need to insert  note of caution though in that the sample size is small and often drawn from a single location.


I also collected small amounts of seed for 29 species, and measured length and width either under x40 or x100 magnification.   Generally I counted at least 10 seeds to give a reliable estimate, but in some cases only one or two.  The length; width ratio was not a good discriminator because long seeds were generally thinner and short seeds fatter, as if the volume was roughly the same (I need to look at this further).   The average seed length does though offer potential to discriminate, and again interestingly G, conopsea is a long way from A. pyramidalis.  



Also the genera are broadly grouped by seed length but this is accentuated when the seed length is plotted against the pod length : width ratio.   Clear clusters for different genera can be seen.

This chart seems to provide a way of discriminating between genera - dactylorhiza from gymnadenia say, and then the seed length and pod length : ratio might hint at species identification, but it is early days.  Too late this year to do any more work so a project for next year confined probably to those genera with several species such as the marsh and fragrant orchids and the helleborines, so that is the summer dealt with.    I also need to look at the literature - there is probably a whole lexicon on this and I need to compare and contrast, so that is winter dealt with also.

Monday, 23 October 2017

Orchids under the microscope

There was a time, when we lived on Skye, that I would be out and about in any weather.  Living down south I have got soft.  Because it was windy and wet at the weekend I spent time indoors dealing with the mass of photographs and information I gathered on orchids over the summer months.   I am interested in whether they can be reliably identified when not in flower, and I have concentrated on the edges and tips of leaves typically under x100 magnification, leaf venation, whether there are stomata before moving on to seeds (x100 magnification and seed pods.  The leaf characteristics I have compared to the descriptions in Poland and Clement (The Vegetative Guide to the British Flora), getting to grips with crenate and papillose margins.

I have summarised these in a PowerPoint files and there are some interesting differences.  For example P&C use habitat to differentiate between the three Fragrant orchids.   It works a lot of the time but not always; yet I think there are some subtle differences in the leaf characteristics - occasional stomata or not, edge characteristics and probably seed size (or more particulary the ratio of length to width).  This is an example of the presentation for one of the fragrants - chalk fragrant (Gymnadenia conopsea)




I collected data for around 30 species out of the total of 53 (?) in the UK and have so far summarised around a half.   Obviously I avoided the Schedule 8 plants and others that are rather rare and you would not stumble across them unless you were purposefully looking for them in a known location. One weakness though is that I have the very smallest of sample sizes for each but I am hoping next year to rig up something that can take at up to x60 magnification in the field.

Quite what I do with the work when completed, I am not yet sure!

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