White poppy

I found this white corn poppy Papaver rhoeas on the edge of a barley field near Egglestone in Teesdale last week. It's undoubtedly a genetic mutation that has prevented scarlet pigment formation in the petals but, oddly, not in the stamen filaments.

It was a similar mutation, that produced pale petal edges, found by Reverend William Wilks near his rectory garden at Shirley near Croydon in 1880, that led to his breeding of the famous Shirley poppies - a strain that's still on sale in garden centres.

Scarlet corn poppies have become a symbol of remembrance of the sacrifice and senseless slaughter in wars since the end of World War 1. White poppies were adopted  by the pacifist movement, in remembrance of the dead and as part of the No More Wars movement, in the 1920s, as a symbol of peace. 

Pteridomania and an obsession with mutants

Thursday's Guardian Country Diary describes a fragment of mature old woodland at Wolsingham in Weardale whose fallen, decaying trees support a wealth of wildlife, including ...

..... this rather lovely epiphytic polypody fern that was attached to an oak branch that had been torn off by the gales. The golden structures on the underside are the sporangia, ripe and releasing spores. You can read about the full life cycle of ferns by clicking here and see some more close-up and microscope pictures of the sporangia by clicking here.



Picture by Helen Allingham, originally published in the Illustrated London News July 1871
http://en.wikipedia.org/wiki/File:Pteridomania.jpg

The golden age of fern popularity was in Victorian times, during a period that has come to be known as Pteridomania. Then the obsession with collecting and growing these plants reached an all-time high, so much so that the population sizes of some native ferns (like holly fern in Teesdale and all the filmy ferns) were reduced to the point where they are now endangered species in our flora. The ladies in the image above are well equipped for digging up choice ferms, although brambles must have played havoc with those dresses.

Advert from Choice British Ferns: Their Varieties and Culture by Charles T Druery F.L.S.(late 19th. century).

Commercial nurseries like W. andJ Birkenhead made a good living out of selling ferns, club-mosses and selaginellas to those who couldn't get out into the countryside to dig them up. The fern craze generated a wealth of popular and scientific literature on these plants, with books like .....

British Ferns and their Allies: comprising the Ferns, Club-mosses, Pepperworts and Horsetails by Thomas Moore F.L.S., F.H.S. (1881)

...... Thomas Moore's British Ferns and their Allies, which described them and told readers where to find them, as well as providing detailed advice on how to grow and propagate them. 

Remarkably, pteridomania wasn't confined to adults; there were fern books for children, like Francis Heath's Fairy Plants: a Fern Book for Children. In his preface he wrote "There is probably no part of the beautiful realm of Botany capable of offering so much fascination for young people as that which is dominated, so to speak, by ferns; and it is because I can conceive of no branch of a delightful subject so likely to incalcate ideas of gracefulness and to instil elevating, indeed ennobling, thoughts, that I have written a fern book for children".

Decorated initial letter from Fairy Plants: a Fern Book for Children by Francis Heath

I suspect that the thoughts of most 21st. century 12 year-olds, unwrapping such a book given as a present, would be far from ennobling. 

So why did ferns become so popular?

Illustration from Ferns and Fern Culture by J. Birkenhead F.R.H.S. (1897)

One reason was they did well as house plants in shady Victorian drawing rooms dimly lit my gas lamps, especially if they were grown in the humid confines of Wardian cases, like the ornate examples above.

Illustration from Ferns and Fern Culture by J. Birkenhead F.R.H.S. (1897)

Perhaps the ultimate expression of Pteridomaniacal one-upmanship was to construct a shady, rocky fernery in your garden.

Illustration from the Fern World by Francis George Heath (1879)

This, perhaps, was the ideal - a reconstruction of that shady woodland stream where you originally stole your plants from. The picture caption gives some idea of the effect they were hoping to achieve: 'We look with wonder upon a fairy, dreamy scene of clustering ferny forms in fascinating association with mossy rocks an flowing water'.

Another reason was that the elaborate fractal geometry of fern fronds appealed to Victorian arts and craft taste, in jewellery such as this brooch, and in ....



.... garden furniture. The flatness of a fern frond lent itself to recreation in cast iron or in applied patterns on decorative objects.

The fern craze died out in 1914, but not before it had produced one more fascinating botanical obsession, with monstrosities.



Illustration from Ferns of Great Britain and their Allies the Club-mosses, Pepperworts and Horsetails by Anne Pratt (1855)

This is the typical 'wild type' hart's tongue fern Phyllitis scolopendrium.....

Illustration from Choice British Ferns: Their Varieties and Culture by Charles T Druery F.L.S.(late 19th. century).

....... and these are some of the multitude on hart's tongue mutants that Victorian fern-fanciers raised and which many prized as the gems in their collections. Similarly, .....

...... this is the wild type polypody Polypodium vulgare ....

Illustration from Choice British Ferns: Their Varieties and Culture by Charles T Druery F.L.S.(late 19th. century).

...... and these are some of the many mutants of the same species that were cultivated, most unrecognisable as polypody.

Although Gregor Mendel published his experiments in 1865 his discoveries on inheritance remained unrecognised until 1900, so the Victorians knew nothing about the genetic mechanisms that generated such mutants.It would be more than a century before the science of plant developmental genetics would reveal the ways in which simple gene mutations can generate such spectacular variations in leaf developmental pathways.

Three-headed Monster

We found this three-headed corn poppy in Teesdale this morning. Sometimes abnormalities like this can be caused by herbicide sprays but, since there were other perfectly normal flower stems on the same plant, I think this was simply a chance developmental aberration. The flower stem is flattened like a plank - fasciated in botanical parlance - and this sometimes happens when growing points that would normally develop into separate shoots become joined together. There can be a variety of causes, including physical damage by an insect or pathogen, infection by the bacterium Rhodococcus (Corynebacterium) fascians, environmental shock or a genetic cause. There are other examples of fasciation here and here.

Here's a normal one...

A Dandelion with a Difference

I found this strange-looking dandelion in Newcastle this afternoon, growing beside a footpath in the city. Unlike typical dandelions (see picture below) which have a spiral whorl of florets each with as single long petal with a toothed tip, with very long petals around the margin of the flower head, this one had very short spoon-shaped petals throughout, so the flower resembled a pom-pom with numerous long styles, each tipped with a bifid stigma, sticking out of it. Quite decorative for a dandelion. There are mutant varieties of chrysanthemum sold commercially that are very similar in form - but a lot larger.

This (above) is a typical dandelion inflorescence. Normally each individual dandelion floret is quite a complicated affair (see here for details) with the long style elongating through a tube of pollen-laden stamens, followed by the splitting of the stigma tip to reveal its receptive surface - a complex arrangement that is totally redundant because dandelions set seed without the need for any fertilisation by pollen, by a process called apomixis. The seeds that are produced are all clones of the parent - so in a week or two, when the flowers have run to seed, I'll go back to this abnormal plant and collect some - they should breed true and produce exact copies if this is a genetic mutant.
 

The other curious aspect of this mutant, seen here from above, is that all the florets are female - there is no trace of stamens or pollen. It seems the mutation that truncates the petals also inhibits the development of the stamens.

There's more on dandelions here.

Glastonbury Thorn aka Roddymoor Pit-Heap Thorn

The Glastonbury Thorn of ancient myth is said to have sprung from the walking stick of Joseph of Arimathea while he slept near the ancient island of Avalon, now familiar to thousands of festival goers as Glastonbury Tor. When he awoke his stick is said to have taken root and sprouted leaves and flowers, so he took root too and introduced Christianity in Britain, so the story goes. In Mediaeval times a hawthorn that grew on the site and flowered in late winter and again in May was believed to be the very same plant. This twice-flowering hawthorn apparently had two trunks, one of which was destroyed in the reign of Elizabeth the First and a second which was finally destroyed in the Civil War by Roundheads. Winter-flowering hawthorns have been planted there since, reputedly from cuttings of the original plant and I believe that one still grows there.........but we have another example growing on an old colliery spoil tip at Roddymoor, up here in County Durham.

These twice-flowering, winter - and spring-blooming hawthorns have been reported from time to time in other parts of Britain and they are all likely to be genetic mutants whose normal response to lengthening days – a signal for bud-burst and flowering, has become confused. This particular specimen was planted about 40 years ago on the old Roddymoor pit heap, in an experiment to see which plants would establish in rock, poor soil and coal dust that was parched in summer and waterlogged in winter. Happily it’s still there, growing slowly but surviving. I picked a twig about three weeks ago which is now in full flower in a vase on my desk today - and is portrayed above.

The plant has several peculiarities, possessing few thorns and bright red buds - see photo above, taken about three weeks ago while there was still deep snow on the ground and showing bud scales beginning to loosen even then. It’s also Midland hawthorn Crataegus laevigata (identifiable by its pair of stigmas), and not the common hawthorn C.monogyna which predominates hereabouts.

Hawthorn is a genetically variable species, notably in its response to spring. You only need to look along a stretch of hedgerow in late February to see some plants almost in full leaf and others still with tight buds that show no propensity to produce leaves until late March. Our local ‘Roddymoor Thorn’ is, I guess, just an individual from the extreme end of this spectrum of response to lengthening days. Still, it’s in pole position to respond to climate change, early springs and milder winters – although this winter hasn’t done it any favours.


There are some other peculiar hawthorns hereabouts, including a yellow berried one which I must remember to photograph next autumn.