Sunday, 23 April 2017

Two Messed-up Coins

Billon antoninianus of Claudius II Gothicus, 268-270 CE.
Billon antoninianus of Claudius II Gothicus, 268-270 CE.
I occasionally post something about ancient coins.  There are two in this post that I bought recently for very little money.  They both look rather messy and it's hard to make out their designs, which is why they were particularly cheap, though even well formed coins of this era are not at all expensive.

I bought them because they hold information.  You can visualise Roman mints of this era as being very busy and not very discriminating.  The dies they made and used were roughly figured and very stylised.  They didn't filter out mistakes; those went into circulation along with the good coins.

There might have been up to four people working with each die pair.  One would place the blank on the bottom die, which might be held by another worker or maybe fixed in place.  This die would have the head image hollowed out.  Another would place the top die with the reverse image on top of the blank, and yet another would hit it with a hammer, at least once, maybe more than once.

What's happened with the top coin is that instead of the struck coin being cleared out of the way, it has flipped over and has still been half in the die when it was hit again.  So, overlying the head image is part of the reverse design, and on top of the reverse, part of the head.  You can see a sideways image of the crown.

Double strikes are not rare, but they are usually a just a sideways shift of the coin between hits,  so that two similar images are superimposed.  This one is a bit more interesting.

Billon Antoninianus of Tetricus I or Tetricus II, 271-274 CE.
Billon Antoninianus of Tetricus I or Tetricus II, 271-274 CE.
This second coin is more complicated.  One side looks like a mirror image of the other.  The first coin has stuck in the lower die, and another blank has been placed on top of it.  This coin therefore has a normal, raised reverse image from the top die, and a sunken and flipped reverse image on what should be the heads side.  The raised image on the first coin has made a sunken image on this one.  This sort of minting error is known as a brockage.

These are not the only kinds of mint errors.  It is also possible to have a die clash, where there has been no blank between the dies when they have been struck.  This damages the dies themselves, and all subsequent coins made with those dies look wrong.  There's a good example on one of Doug Smith's pages here: Brockages and Clashed Dies which also shows some nice brockages.

You can tell a coin is a die clash if you can find more than one of exactly the same error, as Doug's page demonstrates.  In fact, I have one of the very same type as his:

Silver denarius of Julia Domna, "Emesa" mint, 194 CE.
Silver denarius of Julia Domna, "Emesa" mint, 194 CE.
And at least one other is known to exist. You can see from their outlines that this one and Doug's two are all different coins, but the error is identical.  So they must have been struck from the same damaged die.


Wednesday, 19 April 2017

Suburban Wildflowers

Field Forget-me-not, Myosotis arvensis.  Coney Hall, 10 April 2017.
Field Forget-me-not, Myosotis arvensis.  Coney Hall, 10 April 2017.
I have not been out to any new sites this year, but I keep taking photos of plants I see near my home.  Here are some photos of suburban wildflowers from one particular footpath that runs between two roads.  It's unusually rich in flowers, both showy and inconspicuous.

It's common to find Wood Forget-me-not in the suburbs because it is planted in gardens and seeds itself easily.  But this looks like its field relative, with smaller flowers. 

Field Forget-me-not, Myosotis arvensis.  Coney Hall, 10 April 2017.
Field Forget-me-not, Myosotis arvensis.  Coney Hall, 10 April 2017.
Most of these photos show several wildflowers because they all grow close together.  In this shot, surrounding the forget-me-not are some Cornsalads and, at bottom right, a Common Chickweed.  Just below the centre is a Petty Spurge, which has tiny green flowers that you can only make out in this shot if you already know they're there.

Cornsalad, Valerianella species.  Coney Hall, 10 April 2017.
Cornsalad, Valerianella species.  Coney Hall, 10 April 2017.
This is a bigger specimen of the Cornsalad.  I won't be able to tell the species until it fruits.  It's not at all common and is really a weed of arable land.  I was pleased to find one little plant on Hayes Street Farm last year, and then I could never find it again when it should have had fruits.  This one will be harder to lose track of.

Cut-leaved Crane's-bill, Geranium dissectum.  Coney Hall, 10 April 2017.
Cut-leaved Crane's-bill, Geranium dissectum.  Coney Hall, 10 April 2017.
A Cut-leaved Crane's-bill with a couple of small flowers.  Also in this photo are leaves of some other wildflowers.  In the centre, a Common Field Speedwell.  At bottom right, a Dove's-foot Crane's-bill.  At bottom left, a Lesser Celandine.  Middle left, some small Ivy-leaved Speedwells.

Common Field Speedwell, Veronica persica.  Coney Hall, 16 March 2017.
Common Field Speedwell, Veronica persica.  Coney Hall, 16 March 2017.
Here's a flower on a Common Field Speedwell.  There are half a dozen common speedwells.  You can tell this one by the leaf shape and that it has a single blue flower from each leaf axil.

Cow Parsley, Anthriscus sylvestris.  Coney Hall, 10 April 2017.
Cow Parsley, Anthriscus sylvestris.  Coney Hall, 10 April 2017.
This is just the start of the Cow Parsley season.  Many country lanes will be lined with a froth of white in a week or two.  It's very common and grows fast and well. 

In the foreground are some more Lesser Celandine leaves.  The blue flower in the background is a Garden Grape-hyacinth, and true to its name this is a garden escape.  The wild variety has a much more subdued flower colour.

Green Alkanet, Pentaglottis sempervirens.  Coney Hall, 10 April 2017.
Green Alkanet, Pentaglottis sempervirens.  Coney Hall, 10 April 2017.
This Green Alkanet is one of the commonest of our local wildflowers, as well as being one of the showiest.  It grows furiously all spring and summer, flowering all the time.  You could cut this down today and it would be flowering again in two weeks. 

Behind it is some Groundsel, which has no petals on its small yellow flowers.  In the foreground are some I've already shown: Cornsalad, Field Forget-me-not and Petty Spurge.  Growing up the fence are some stems of Cleavers, not yet in flower.

So, you can actually do quite a bit of botanising along 25 yards of one footpath!  And there are a dozen other species, too,  not all in flower at the same time.

Tuesday, 11 April 2017

Sleeping Cuckooflowers

Cuckooflower, Cardamine pratensis.  Withyham, 5 April 2017.
Cuckooflower, Cardamine pratensis.  Withyham, 5 April 2017.
I haven't been to many countryside sites recently as most of my driving has been up and down to a new house I am getting ready for occupation.  But I do still photograph things I pass by, and I could not resist taking my camera along to capture some of the banks of Cuckooflower that are flourishing on roadsides near my new place. 

The Cuckooflower is an early Spring beauty.  It's not rare in the London Borough of Bromley, where I live now, but you see it in much smaller numbers.

It's sometimes called Lady's Smock or Milkmaids.  And I discovered this year that it rests its flowers at night.  The photo above was taken just after noon.

Cuckooflower, Cardamine pratensis.  Withyham, 5 April 2017.
Cuckooflower, Cardamine pratensis.  Withyham, 5 April 2017.
This one was taken at 8 am in the same place.  Flowers all drooping, not yet awake.  Dew still on the grass.

Wednesday, 22 February 2017

Hazel Flowers.

Female Hazel flower, Corylus avellana.  The Knoll, Hayes, 19 February 2017.
Female Hazel flower, Corylus avellana.  The Knoll, Hayes, 19 February 2017.
Just a short post .. You are probably familiar with the cheerful yellow hazel catkins that appear at this time of year.  You might not have noticed these inconspicuous female flowers that usually appear just after the tree has shed its pollen.

The flowers do not need to be conspicuous because the pollen is spread on the breeze, not by insects.

Male Hazel flowers, Corylus avellana.  The Knoll, Hayes, 19 February 2017.
Male Hazel flowers, Corylus avellana.  The Knoll, Hayes, 19 February 2017.
Here's a close-up of catkins on the same tree. You can see that although there are grains of pollen stuck to it, the actual anthers are all empty and the yellow tone is much muted.

Friday, 3 February 2017

Ultraviolet Lichens

Xanthoria parietina on a brick wall in Hayes by UV light. 21 January 2017.
Xanthoria parietina on a brick wall in Hayes by UV light. 21 January 2017.
Some lichens light up in vivid colours under ultraviolet light.  You have to go out in dark night to see this properly.  This can be an aid to identification, but the most vivid ones are pretty easy to identify anyway ..

Xanthoria parietina on a brick wall in Hayes in daylight. 22 January 2017.
Xanthoria parietina on a brick wall in Hayes in daylight. 22 January 2017.
The top photo is the right-hand patch of this vividly coloured lichen, Xanthoria parietina.  I have adjusted the photo considerably to bring it to roughly what the naked eye sees.  The camera does not pick up the UV light, but there is a strong visible mauve light that goes along with it when the UV torch shines, and I balanced that out.  (I have put the technique I used at the bottom of this post.)  The eye can adjust to that, but the camera needs help.

The UV photographs are interesting.

Lichen community on a brick wall.  Left: daylight.  Right: UV light.
Lichen community on a brick wall.  Left: daylight.  Right: UV light.
There are 7 or 8 species of lichen in this small space, just a few square inches.  You can see some more of the Xanthoria on the right.  There are some other leafy lichens, green ones, and some that form crusts of various green, yellow and orange shades.  (Also, some moss.)

Looking at this, you might think that all the yellowy-orange lichens glow orange in the UV light, but that's not so - there is a patch towards the top right of a yellow species that doesn't respond to the torch.  That's probably a Candellaria species, which in theory should have a slight glow, but there is none here.  Another species that has not read the book, perhaps.  The difference in glow is because there is more than one chemical that can give a lichen a yellow colour.  So you can use this UV glow effect to help identify a lichen.

Lichen community on a brick wall.  Left: daylight.  Right: UV light.
Lichen community on a brick wall.  Left: daylight.  Right: UV light.
But in this pair of photos from nearby, you can see at the top right an orangish lichen that glows faintly under the UV torchlight, which can be compared with the patches of Xanthoria at the top left.  I think the white one is just reflective, not actually glowing.  I can not give you any other species names for this photo.  Maybe when I know more ...

Lichens are various and complicated and I have only just scratched the surface (that's a joke if you are a lichenologist.)

=======================================================================

How to remove the mauve tint from photos of UV glow using a good camera and Photoshop:

First, photograph your UV torchlight on a white background in a dark place.  Use this photo as the basis for a custom white balance setting.

Then photograph your subject at night, shading with your body from any street lighting and evening out the UV torchlight across the subject as much as you can.  This can be tricky if you are holding everything in your hands.

Take a high quality JPEG from the camera and edit in Photoshop.  Sample the mauve background colour cast from a light area with the eye dropper tool.  Create a new empty layer and fill it with the sampled colour.  Invert this layer's colour to get its opposite, which will be a green shade (Control-I does this).  Make that layer a colour type layer.  Adjust its opacity until there is as little mauve or green as possible in the resulting picture.  You're done!  But as you can see from my photos above, the result does vary a bit from shot to shot and no one photo should be accepted as definitive.  There are variations in cameras' sensors and software, also the exact shades sampled in Photoshop, and computer monitors vary too.

Friday, 27 January 2017

Things Grow on Trees.

Oak with Flavoparmelia caperata.  Hayes Common, 30 December 2016.
Oak with Flavoparmelia caperata.  Hayes Common, 30 December 2016.
Things grow on trees, and I don't mean just fungi, which grow on trees because they are eating the trees.  I mean things that just use the trees as a place to rest, where they can get some light, and stand less chance of being grazed or trodden on.

In the UK, it's mostly lichens, mosses and liverworts.  Other countries with different biota and climates can have a much more extensive range of plants that behave like this.  The tree in the top photo has some moss and some large patches of a distinctive bluish-green lichen, Flavoparmelia caperata.  As you can see, you don't need to go far from a road to find something like this.

Usually, they are high up in the trees, but it is possible to find spots like this where they are arrayed near the ground where you can get a good look.

Oak branch with a range of mosses and lichens.  Hayes Common, 30 December 2016.
Oak branch with a range of mosses and lichens.  Hayes Common, 30 December 2016.
As here; some of it is high up, but there's also that long, long low branch covered with greenery.

Evernia prunastri, Oakmoss.  On an oak branch on Hayes Common, 2 January 2017.
Evernia prunastri, Oakmoss.  On an oak branch on Hayes Common, 2 January 2017.
In oak woods, there is a great deal of this shrubby Oakmoss, actually a lichen despite its common name.  You can see lots of clumps that have fallen to the ground, perhaps disturbed by squirrels.  It grows on the small branches and twigs.  There are also many other species that are easy to find.

On the trunks you find more of the leafy lichens like the one in the top photo.  Also, things like this:

Metzgeria furcata, Forked Veilwort, on oak.  Hayes Common, 30 December 2016.
Metzgeria furcata, Forked Veilwort, on oak.  Hayes Common, 30 December 2016.
This is on an oak trunk.  You might think it looks mossy, but close up:

Metzgeria furcata, Forked Veilwort, on oak.  Hayes Common, 30 December 2016.
Metzgeria furcata, Forked Veilwort, on oak.  Hayes Common, 30 December 2016.
Those delicate flat forked straps are not moss leaves at all, but the thallus of a common liverwort, Metzgeria furcata. 

You don't need to go into the woods to see this sort of thing.  Here's a local street tree.

Tree on Bourne Vale, Hayes, 13 January 2017.
Tree on Bourne Vale, Hayes, 13 January 2017.
The marker shows where I spotted a tiny clump of moss.

Syntrichia laevipila, Small Hairy Screw-moss, on the bark of a tree trunk on Bourne Vale, Hayes, 13 January 2017.
Syntrichia laevipila, Small Hairy Screw-moss, on the bark of a tree trunk on Bourne Vale, Hayes, 13 January 2017.
I have rotated the photo to put the moss in a more familiar orientation, but you can see it's growing on rough bark.  There are also several lichens nearby.  There are not many records of Syntrichia laevipila in this area, so this was a good find.

From a distance, this tree might look quite bare without its leaves, but if you look at the higher branches from a bit closer:

Lichens on a tree on Bourne Vale, Hayes, 13 January 2017.
Lichens on a tree on Bourne Vale, Hayes, 13 January 2017.
You can see that it is absolutely covered with, not only lichens, but there will also be mosses, liverworts and algae.  And that's on a busy suburban street. 

I haven't mentioned algae before, but only because they are so small that I can't produce decent photos of them.  They are there alright.

Saturday, 21 January 2017

Three Related Lichens

Lecanora chlarotera, Lecanora dispersa and Lecanora muralis.  January 2017.
Lecanora chlarotera, Lecanora dispersa and Lecanora muralis.  January 2017.
This is a good season for lichens, so I have been taking some photos of them.

These are three species from the same genus.  The first one, Lecanora chlarotera, grows typically on trees, in a patchwork with some soepcies from different families.

Here's a typical example.

Lichens on a tree high on Kemsing Down, 12 April 2014.
Lichens on a tree high on Kemsing Down, 12 April 2014.
Here it's in a patchwork with Lecidella elaeochroma (black dots) and Physcia tenella (small, leafy).

Lecanora muralis, on the other hand, could not have a more different environment.  It grows all over the pavements, often in busy areas.   It prefers not to be walked on too much, but can survive a bit of footfall.

Lecanora muralis,  pavement of Mead Way, Hayes, 29 January 2016.
Lecanora muralis,  pavement of Mead Way, Hayes, 29 January 2016.
Here it is on asphalt.  It can easily be mistaken for chewing gum at a casual glance.

The third example, in the middle of the top picture, is Lecanora dispersa.  This is either rarer or just less often recorded.  It's not so easy to see, because what you do see is little more than an array of the fruits, without a visible thallus.  I found that one right next to L. muralis, and I only found it when looking at my photos.

Lecanora dispersa on the pavement on Bourne Way, Hayes, 12 January 2017.
Lecanora dispersa on the pavement on Bourne Way, Hayes, 12 January 2017.
Those light orange dots are another lichen species - I suspect young spots of a Candelariella - and I think the black areas are probably yet another, though I can't be sure, not being a lichen expert.

Monday, 16 January 2017

Green and Yellow

Bisporella citrina, Lemon Disco.  High Elms Country Park, 2 January 2017.
Bisporella citrina, Lemon Disco.  High Elms Country Park, 2 January 2017.
This odd little fungus is Lemon Disco, Bisporella citrina.  The individual blobs are very small, but there can be a lot of them.  This orange display drew me to a log by the side of a path through High Elms Country Park.

Log with two fungus species.  High Elms Country Park, 2 January 2017.
Log with two fungus species.  High Elms Country Park, 2 January 2017.
I came for the lemon disco, but stayed for that blue-green stuff on the right .. that is Green Elfcup, a fungus which is quite common, but rarely seen in fruit.  We know it's common because the wood it grows in is stained dark green even when it's not fruiting, and that is found quite often.

Chlorociboria species, Green Elfcup.  High Elms Country Park, 2 January 2017.
Chlorociboria species, Green Elfcup.  High Elms Country Park, 2 January 2017.
Here are the oddly-coloured fruiting bodies.  It's one of two possible species that can't be told apart from a photograph.

That's a great display for a mycologist, though in my opinion, rather an ugly colour ... the wood turns out quite nicely, though.  At one time, it was dried and used to create Tunbridge ware, a form of decorative inlaid woodwork.

(The title of this post, "Green and Yellow" was the title of a folk song I knew as a teenager, a version of the song more commonly known as "Lord Randal."  It did not refer to these fungi, though it could easily have done.)

Thursday, 12 January 2017

Showy and Common

Trametes hirsuta, Hairy Bracket.  High Elms Country Park, 8 January 2017.
Trametes hirsuta, Hairy Bracket.  High Elms Country Park, 8 January 2017.
In this post are two rather similar fungi that produce showy displays when they are fresh.  This first one is Hairy Bracket, Trametes hirsuta.  Similar to, and nearly as common as Turkeytail, Trametes versicolor.  The individual brackets are a couple of inches across and, when young, they are quite hairy.

Trametes hirsuta, Hairy Bracket.  High Elms Country Park, 8 January 2017.
Trametes hirsuta, Hairy Bracket.  High Elms Country Park, 8 January 2017.
They can completely cover a dead log, like this.  The colour forms range from light brown to almost black, and the zoning effect you can see here makes it an easily recognisable species (except that there is another similar one - a common problem for identifiers! - which has larger brackets.)

The second fungus in this post also produces many small brackets, and can also cover dead wood.

Stereum hirsutum, Hairy Curtain Crust.  High Elms Country Park, 2 January 2017.
Stereum hirsutum, Hairy Curtain Crust.  High Elms Country Park, 2 January 2017.
It can even have a similar zoned appearance, as you can see here.

Stereum hirsutum, Hairy Curtain Crust.  High Elms Country Park, 2 January 2017.
Stereum hirsutum, Hairy Curtain Crust.  High Elms Country Park, 2 January 2017.
And, as you might expect from its name, it's hairy!

Stereum hirsutum, Hairy Curtain Crust.  Topside and underside.  High Elms Country Park, 2 January 2017.
Stereum hirsutum, Hairy Curtain Crust.  Topside and underside.  High Elms Country Park, 2 January 2017.
But the hairs last longer.  Old Turkeytail does not look particularly hairy, and the brackets seem quite thin.  And if you are ever in doubt about which one you are looking at, the underside is completely different.  That last photo shows the underside of Hairy Curtain Crust on the right.  Here is the underside of Turkeytail:

Trametes versicolor, Turkeytail.  Underside.  High Elms Country Park, 8 January 2017.
Trametes versicolor, Turkeytail.  Underside.  High Elms Country Park, 8 January 2017.
Very obviously covered with pores. 

Wednesday, 4 January 2017

Three Fields from 2016

Hayes Street Farm with Sowthistles and Scented Mayweed.  5 July 2016.
Hayes Street Farm with Sowthistles and Scented Mayweed.  5 July 2016.
Here are three fields from a folder of things I thought I might put on the blog.  This one is a field on Hayes Street Farm, quite close to my house, which I think must have been sown for green manure.  It was harvested several times during the year.  These plants all occur naturally in this area, but so many similar types all together is not normal.

But because it wasn't fertilised or tended, this field produced a great crop of smaller wildflowers during the year, some of which are quite scarce.  Keep it up!


View of the valley behind Leaves Green, 16 May 2016.
View of the valley behind Leaves Green, 16 May 2016.
This is one of several dry chalky valleys in the London Borough of Bromley, which extends well out into the countryside.  The yellow flowers are buttercups.

View across fields to the Enfield Road bridge over the River Medway, Leigh, 12 May 2016.
View across fields to the Enfield Road bridge over the River Medway, Leigh, 12 May 2016.
This spot near Leigh is a good area for botanists.  This particular field doesn;t seem to have anything unusual in it, but the display of dandelion flowers and seed heads makes it worth seeing.

But flowers are for the warmer months.  Next time, something more wintery.