Thursday, December 18, 2014

Cormorants' coat of many colours

Thursday's Guardian Country Diary is about cormorants.

Look at a cormorant's plumage from a distance and it seems as though it's coal-black, but a bit of sunshine makes all the difference.

Bright sunlight glancing off their outstretched wings reveals a bronze iridescence ...

..... but in a more diffuse light there's indigo in the chest and wing feathers....

.... while this juvenile has a hint of bottle green in the crown and tail plumage.

All 'a trick of the light'.

Sunday, December 14, 2014

Attack of the killer bootlaces

This strange black network, that grew under the bark of this pine tree when it was alive, identifies the fungus that killed it - honey fungus Armillaria mellea.

Honey fungus is perhaps the most notorious of all fungal tree killers, not just of forest trees but also specimen trees of many species in gardens and arboreta.

The fungus kills the host by producing this network of rhizomorphs - bundles of hyphae that look like boot laces. They digest the living tissues between the bark and the water-conducting xylem that forms the woody core of the tree. The victim in this photo is a beech tree.

The rhizomorphs are doing their deadly work well before the fungal fruiting bodies appear. Often the first symptoms are individual branches of the tree dying, but it can take years to completely kill the tree. Often the roots are killed and then it topples in a gale. Meanwhile the rhizomorphs also grow downwards over the roots and out through the soil, until they find roots of a neighbouring tree that they can invade. 

Wednesday, December 10, 2014

Some interesting fungi

Striated bird's nest Cyathus striatus growing on decayed wood. Each of the cup-shaped 'nests' contains egg-shaped structures called peridioles that contain the spores. Photographed in Slindon Woods, near Chichester, West Sussex.

In these field bird's nests Cyathus olla you can see the 'eggs', which are attached to a fine thread and are splashed out of the 'nest' by raindrops and become entangled in surrounding vegetation. When they dry out they then discharge their spores into the airstream. For more detailed explanation, click here.These specimens were photographed in Durham, growing in a garden border of perennial plants that had been cut back for the winter.

Bog beacon Mitrula paludosa, a tiny jelly fungus.

These bog beacons were growing on a waterlogged bed of decaying spruce needles in Hamsterley Forest, Co. Durham.

Eyelash fungus Scutellinia scutellata growing on wood chips after tree felling in Hamsterley forest, Co. Durham. Each of the orange cups is surrounded by long hairs that look like eyelashes.

Terracotta hedgehog fungus Hydnum rufescens. The majority of toadstools carry their spores on radial gills or on the surface of pores but in this genus the spores are attached to tooth-like structures under the cap. Growing under beech trees in Hamsterley Forest, Co. Durham.

Thursday, December 4, 2014

Bramble leaf rust

Thursday's Guardian Country Diary concerns the fungus that produces these colourful symptoms on bramble leaves - bramble leaf rust, Phragmidium violaceum.

The fungus initially develops within the green leaf, causing purple patches, but when the leaf begins to die and loses its chlorophyll this vibrant 'plums and custard' colour scheme turns the leaves into some of the brightest objects in the hedgerow in early winter. 

These clusters of spores erupt through the underside of the leaf as it begins to die.

The individual spores are just about visible with a camera macro lens but for a clear view you really need a microscope.

These are the individual spores viewed at about  x20 with a low power stereomicroscope, and .....

.... here they are seen though a compound microscope at a magnification of around x100, showing their very distinctive club-shaped structure, with 4-5 spores on a stalk.

In Victorian times rust fungi were popular, easily accessed subjects for amateur microscopists and in 1870 the somewhat eccentric naturalist Mordecai Cubitt Cooke devoted a whole book, entitled Rust, Smut, Mildew and Mould: An Introduction to the study of Microscopic Fungi, to their study. It’s hard to imagine such a title attracting many buyers now but in Cooke’s day, without thedistractions of television, radio and the internet, microscopy was a very popular pastime and the book ran through four editions in 20 years.

Mordecai Cubitt Cooke
[public domain image, source]


Cooke was evangelical when it came to promoting the delights of microscopy, opening his first chapter with the confidant assertion that “everyone who possesses a love for the marvellous, or desires a knowledge of some of the minute mysteries of nature, has, or ought to have, a microscope.” In his day the lady of the house would be perfectly happy for her husband to retreat to his study for a close look at smut – or rusts, mildew and mould – in the knowledge that he would be advancing the cause of science.


A plate from Rust, Smut, Mildew and Mould. The spore of Bramble leaf rust is illustration number 35.

Saturday, November 29, 2014

Kirkby Stephen's macaws feeding on beech mast

Kirkby Stephen, in the Eden Valley in Cumbria, has a locally famous flock of free-flying feral macaws. It seems that beech mast is their favourite food - all these photographs were taken from under a beech tree outside the local fire station this afternoon.

These spectacular birds originally belonged to a local farmer and conservationist called John Strutt, who died a couple of years ago. You can read all about this remarkable man and his amazing free-range parrots by visiting this web site.

There's also more about him here.

Thursday, November 20, 2014

Fine fungi

After a bit of a slow start here, the crop of interesting autumn fungi is beginning to improve, no doubt because of recent rain. We found these three species in the Tyne valley near Wylam today. 

Variable oysterling Crepidotus variabilis, growing on dead gorse stem

Beech woodwort Hypoxylon fragiforme, looking very like Christmas baubles. Growing on a fallen tree trunk.

Purple jellydisc Ascocoryne sarcoides, looking like something that belongs on a butcher's slab. Growing on a fallen tree trunk.

A luxuriance of lichens

Today's Guardian Country Diary is about the way in which the right combination of habitat factors - light, humidity and shelter from the wind - can coincide to provide conditions that favour the luxuriant growth of lichens on trees.

All of these lichen species were festooning just three larch trees in a plantation in Hamsterley forest. The trees were at close commercial spacing in neat rows, but only three on the outside row, in a dip in the ground, carried a dense population of lichens. The next row in, about five feet behind, had a few but the row beyond those, that would have been too shaded in summer when the larches carried needles, had none at all.

This beauty, also shown in the four photos immediately below, is (I think) Usnea subfloridana. Its delicate branches don't respond well to being buffeted by gales but in this sheltered location it hung like beards from the trees.

I've yet to identify the following species but they too covered the lower branches of the larches.

Ramalina farinaceae (?)

Hypogymnia physoides (?)

Evernia prunastri (?)

Cetraria chlorophylla (?)

Hypogymnia physoides (?)

Cladonia fimbriata (?) growing on an old larch cone