Yellow Star of Bethlehem (Gagea lutea) - Why so few flowers?

It was the annual count yesterday of flowers of Yellow Star of Bethlehem (Gagea lutea) at Whitehill Wood by the River Evenlode.  A week earlier than last year after a cold Spring, there were no violets, primroses and Wood Anemone just emerging, and too early for toothwort.  We found only one flowering plant of G. lutea, with a few more in bud, a total of nine plants, I think, and fewer than the average for the last 7 years, 13 flowering plants.   We did not rediscover two plants seen in flower earlier in the week; maybe they were chewed off by deer, of which there are lots in the wood.

What is remarkable is how few plants flower.   There are hundreds of non flowering plants, which are distinguishable in leaf, with some experience, from bluebells by the single, hooded basal leaf with a "long, inrolled apex" (Poland and Clement).   I counted plants in a 5m strip on each side of the path (5.5m x 0.4m on the river side, 5.5m x 1m on the other side, a sloping bank), a repeat of last year.

River:  53 non-flowering, 0 flowering (20/0 last year)
Sloping bank:   40 non-flowering, 0 flowering (43/1 last year).

The percentage of flowering plants is tiny, but why?   Do the plants not develop enough once they have germinated to produce a flourishing plant or do they spread vegetatively, (but in that case there would be tight clusters which is not the case)?  It does of course 

Most plants were juveniles, but a few looked robust enough to bear flowers. In the wood above, which slopes quite steeply, there were plenty of leaves but no flowers.  This is replicated elsewhere and also seems to be consistent with the genus.   I remember from visiting years ago that it was also true of G. bohemica in Radnorshire - lots of plants but very few flowers.   

I have looked at the dataset and can find no reliable correlation with climate, other than a very wet June / July in 2012 was it seems linked to no flowers appearing in 2013.

They seem to prefer minimal competition.   There are none where ransoms grow, and tail off where the dog's mercury takes over.   

The one flowering plant faced the river at a point which was deeper than the height of my wellingtons, and the resulting wet feet in slippery mud might offer an excuse for these slightly out of focus pictures.

Westwell Gorse - Orchid Leaves

We went to Westwell Gorse, the BBOWT reserve near Burford today, to see what impact the snow and ice earlier this month had on the emergence of the orchids there.   Actually quite a lot; they were quite bedraggled, much less advanced than a year ago, and quite a number of leaves were damaged.  Rabbits had also been active chopping the tops of two of the plants of which I took an accurate position last year.  Here are a few comparisons of three Early Purple Orchid Plants  (Left = 2017, Right = 2018):

                                              

                            

               

At flowering time, as last year we will make a count to see if the frosts and snow have had a more lasting impact, though it looks as though the rabbits are the bigger problem.

  

Firsts

Some sunshine and warmth.  Could this be spring at last (though snow is forecast this weekend)?

I recorded a few firsts for the year. 

The moth trap 2 evenings ago had the first moths for the year - 3 in total over a 4 hour period:

• Dotted Border (the first I have had here). 
• March Moth (as last year), 
• Oak Beauty (seen in 2016 but not last year)

Dotted Border

 

Oak Beauty

March Moth

The first bees appeared in the garden:

• A queen White-tailed Bumblebee on a hellebore
• Honeybees on crocuses

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

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.

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!

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