Tuesday, September 5, 2017

Hortus Britannicus

I found this first edition of an amazing work of early 19th. century scholarship in an antiquarian bookshop many years ago. J.C. Loudon's Hortus Britannicus lists all the the plants, native and introduced, known to be growing in Britain in 1830.

This is much more than just a list, though, as becomes evident when you read the title page which describes the full scope of this monumental work of reference. 

It is: 

A Catalogue of all the Plants Indigenous, Cultivated in, or Introduced to Britain with the Systematic Name and Authority, Accentuation,Derivation of Generic names,literal English of specific names,Synonyms Systematic and English of both Genera and Species, Habit, Habitation in the garden, Indigenous Habitation, Popular Character, Height, Time of Flowering, Colour of the Flower, Mode of Propagation, Soil, Native Country,Year of Introduction, and Reference to Figures

All this information, in this masterpiece of early 19th. century information technology, is tabulated under column headings. 

This page is the key to the various categories under each heading. 

If you double click on this image it should enlarge enough for the detail to be readable.

Here is a sample page, for species in the genus Primula, the primroses.

But there is more! 

Here is Loudon's method for producing coded plant labels for the garden that correspond to the species numbers in his catalogue, by cutting grooves in a wooden label.

And here is his advice on drying plants, forming a herbarium and drawing plants, flowers and fruits.

J.C.Loudon was a Scottish botanist who also designed gardens and cemeteries and who is also credited with coining the term 'arboretum'. 

Despite suffering from poor health he travelled widely and seems to have been something of a workaholic. He completed Hortus Britannicus after a botched operation to repair a broken right arm, which led to him having it amputated at the shoulder. Undeterred, he quickly learned to write and draw with his left hand.

He died, penniless, in 1843.

You can read his Wikipedia enrty (the source of this image) by clicking here.

You can download a digital copy of Hortus Britannicus by clicking here

Wednesday, August 30, 2017

Magical roundabout

Durham County Council deserves great credit for the way it has planted roundabouts and road verges with colourful cornfield annuals.

This vibrant display is on the roundabout at the junction of the A68 and A689, just west of Crook. The rowan trees in the centre always produce a fine crop of berries but this year the addition of the flowers has produced a stunning display.

Corn marigold, cornflower, ox-eye daisy and corn poppy. A wonderful tapestry of colour.

Managing road verges in this way is a win-win-win strategy. It provides loads of nectar and pollen for insects, reduces maintenance, and makes a superb addition to the landscape.

This roundabout sits at the gateway to Weardale, part of the North Pennines Area of Outstanding Natural Beauty that is famous for its colourful meadows in summer. It provides a wonderful welcome to visitors to the dale. 

Tuesday, August 29, 2017

Painted Ladies

Lately a few painted lady butterflies have begun to appear in Teesdale and Weardale, wafted in by warm winds from the south. It's nothing like the spectacular invasion we enjoyed in 1996, when the first arrivals appeared in early July and bred on thistles to produce a second generation, so that there were enormous numbers by early autumn. Sometimes late invasions arrive in early autumn, as they did in 1903 (see below).

Painted ladies are noted for their infrequent but spectacular invasions and some of the largest of these, according to F.W. Frohawk in his Complete Book of British Butterflies published in 1934, coincided with wet summers in 1879 and 1903. 

This is how Frohawk described them:

"In 1879 the first migratory swarm appeared in North Africa in the middle of April. At Barcelona and Valencia enormous numbers occurred at the end of April and reached the island of Minorca on the first three days of May. On June 15th. vast swarms passed over Sevres, flying all day in a north-westerly direction. Similar flights were seen at Strasburg passing in countless numbers to the north, At Angers, on June 10th., an immense swarm flew over the city; it was estimated that between 40,000 and 50,000 passed along a single street in one hour; they were flying so low that pedestrians were inconvenienced by them. At Bisheim, on June 8th., the same phenomenon was observed and their numbers were so enormous that they darkened the sky. On June 11th. the flight that passed through Steyer in Austria, was so great that between one and two o'clock p.m. 90 to 100 per minute were counted in the breadth of 100 paces, the swarm being estimated at 1,000,000. Similar vast swarms were encountered in other places. 

Again, in 1903, a sudden and great invasion of these butterflies occurred in the autumn. They arrived in hundreds of thousands along the southern and eastern coast and dispersed over the whole of the British Islands. The flight was so vast that it extended from the Shetlands to the extreme south of England and Ireland. Their numbers were so prodigious that they swarmed along the whole of the eastern seaboard, from Durham to Kent, and wherever observations were made on the Scottish coast, they were abundant. The first arrivals of this vast invasion reached our shores on September 18th., and the flight continued for five or six days, their numbers increasing daily."

These butterflies look particularly attractive when you view them from below, with the sun shining through their wings that then resemble stained glass windows.

This individual was in Weardale yesterday, feeding on knapweed.

Thursday, August 3, 2017

Golden-ringed dragonfly

Dragonflies are the subject of my Guardian Country Diary today.

This is the peak period locally to watch these spectacular gold-ringed dragonflies Cordulegaster boltonii, which have the longest body (but not the greatest wing span) of any UK species. We discovered this female in the early morning, torpid after a cool night, resting on a patch of rushes next to a footpath.

There are several prime locations for this impressive insect here in the North Pennines. One of the best is in Hamsterley forest, near Spurleswood beck, which has the kind of crystal clear, highly oxygenated water and stony stream bed that forms a perfect breeding habitat. Another is along the river Derwent near Blanchland in Northumberland. A third is in Weardale, in a shallow stony beck that runs down the hill into the top of Tunstall reservoir near Wolsingham in Weardale.

While I was photographing this individual she began to warm up her flight muscles, first with just the merest hint of a vibration in her wings, until she was like a helicopter on the verge of take-off. Then she let go with those legs, which are of little use for walking but are used for gripping perches and catching prey in mid-air ..... and she was gone, hunting flies over the bracken.

The marvels of dragonfly vision are almost beyond our comprehension. We have trichromatic vision, with sensors that detect red, green and blue, which together define our visual spectrum. Dragonflies have sensors that detect at least five wavelengths, in addition to ultra-violet which is beyond our perception, and some species have thirty sensors that each detect a different wavelength, so their colour spectrum is vastly more complex and subtle than ours.

It's an interesting thought that those bright colours that we admire when we watch a dragonfly are not the colours that they see.

Then there are those massive compound eyes, each composed of thousands of separate facets (ommatidia), which give them highly sensitive flicker vision. When fast-moving objects cross their field of view they are tracked by a succession of ommatidia that convey the information to the brain.

Their amazing eyes, coupled with their speed of flight and extreme manoeuvrability, make them deadly aerial interceptors.

Saturday, July 29, 2017

Some early Amanita toadstools - another symptom of a warmer world?

It seems strange to be blogging about toadstools like these in July ....... I can't recall seeing either of these in Weardale quite this early in the year. Both were photographed yesterday in Backstone Bank wood near Wolsingham in Weardale. There were also numerous larch boletes Suillus grevillei in the larch plantation and some slippery Jacks Suillus luteus amongst the Scots pines, mostly eaten by slugs.

Grey-spotted amanita 
Amanita spissa

Fly agaric 
Amanita muscaria

There is now quite a substantial body of evidence that fungi are fruiting earlier as a result of climate change, and in some cases fruiting in spring and autumn. Various reasons have been suggested, including one that mycorrhizal fungi like these (which form a symbiotic link with tree roots) are receiving more nutrients from the trees that now have a longer growing season. Another is that decay rates in forest soils are increasing as average temperatures rise.

A major survey at Cardiff university in 2007 revealed that some species are fruiting for much longer, with an increase in some species from 33 days in the 1950s to over 75 days.

Maybe summer fungal forays will become commonplace in future.

You can read more scientific research about the links between climate change and fungal fruiting times by clicking here and here and here and here

Sunday, July 23, 2017

Moss pop-guns

It's not very often that I find bog moss (Sphagnum) bearing spore capsules. They are easy to overlook because they are not raised on a long stalk (seta) like the capsules of many other British mosses.

I found these on cushions of Sphagnum growing in a little hillside mire near Wolsingham in Weardale. I'm wondering whether it may have been the very dry spring followed by wet mild weather that triggered rapid growth and their formation.

The capsules remind me of small, round ginger jars.

They are unusual because, unlike most moss capsules that shake spores out through pores or peristome teeth, these literally explode.

As the capsules mature they lose water and the air inside them becomes pressurised. As the walls contract the capsules change shape, from spherical to cylindrical like the rearmost in this photograph. Eventually the lid blows off, sending a mushroom cloud of thousands of microscopic spores, in a vortex like a smoke ring, about ten centimetres into the airstream.

You can watch a high-speed film of the whole process by clicking here and here  

Saturday, July 22, 2017


It's a sign of the high summer when harvestmen appear in our garden. Initially I though this was Leiobunum rotundum, until Richard Burkmar (see comment below) pointed out that it's an invasive, non-native species called Opilio canestrinii which was first documented in Britain in 1999.This species has remarkably long black legs, like L.rotundum, but there is an orange ring around the trochanter ('knee') that I hadn't notice. This male, sunbathing on a leaf in the late afternoon sunshine, is in pristine condition, probably having just reached maturity. Females have a darker saddle-like marking on their dorsal side.

The longest legs are the second pair and key senses of taste, smell and touch are located on these. If you watch them walking through the undergrowth you can see them using these to explore their surroundings.

Harvestmen often lose a leg of two, shedding them if they are grabbed by a bird or caught in a spider's web, and this isn't too much of a problem unless it's the second sensory pair - then they are in more serious difficulties.

For more harvestmen (including pictures of a female Leiobunum rotundum) on this blog, click here.

Opilio canestrinii has spread northwards quite widely since it was first found in Essex eighteen years ago. The Spider and Harvestman Recording Scheme web site (click here) shows that it has reached as far north as Inverness. 

My guess is that it arrived in our garden via a plant from a garden centre. The wholesale and retail garden plant trade provides perfect distribution network for newly arrived arthropod species like this.

Friday, July 21, 2017

A very hairy gooseberry

All over the North Pennines there are traces of small settlements - usually mining communities or sometimes farmsteads - that have long since fallen into ruin. In some cases all you can see is a few piles of stones and the rectangular outline of building foundations, but often you can also find botanical traces of past gardens.

The commonest edible plants in these are rhubarb and gooseberries, which persist for generations, long after the gardeners who originally planted them have been forgotten. At this time of year the gooseberries start to ripen and I always make a point of tasting these, which mare mots likely to be forgotten varieties that are no longer cultivated. There are also scattered bushes well away from gardens, that would have been bird-sown. There is a large gene pool of feral gooseberry varieties out there in the countryside and maybe there might even be some that are resistant to diseases like gooseberry mildew.

This unusually hairy example was growing through an old wall in Teesdale and ripens to a deep ruby red. Its fruits are exceptionally sweet, though you need to rub off those hairs first it you want to eat it uncooked. It probably closely resembles the wild species that originated in continental Europe and which lost most of its bristles during cultivation.  If it was stewed or used to make chutney (gooseberries make excellent chutney) then they wouldn't matter too much.

I've rooted a cutting of this one, that's now growing in my garden. 

Apparently, gooseberries were first domesticated in the Middle Ages and there are records of plants being imported from France in 1275 for planting in Edward 's garden in the Tower of London.

Growing goooseberries competitively, to see who could produce the largest fruits, became popular amongst Lancashire weavers in the 1740s and the heaviest fruits weighed in at over 50 grams, over seven times the weight of the wild ones. By the early 1900s almost 1000 named varieties existed, cultivated by gooseberry clubs.

There is still an annual gooseberry growing championship at Egton Bridge near Whitby in North Yorkshire, which you can read about by clicking here. This year's show is on 1st. August.

The world record currently stands at 62 grams. 

Thursday, July 20, 2017

Soundtrack to Summer

Today's Guardian Country Diary is about grasshoppers.

These lovely insects, that provide a soperific soundtrack to late summer, are sun-loving so their greatest species diversity in the UK is concentrated in southern England.

We have two common species here in the North Pennines ......

... the green grasshopper  Omocestus viridulus....

.... and the meadow grasshopper Chorthippus parallelus.

Both 'sing' by stridulating - dragging those pegs on their hind femur over the hard edges of the wing. The meadow grasshopper has the most varied song and both sexes chirrup, though the female's song is quieter than the male's because those stridulatory pegs tend to be smaller in females.

Males have three distinct songs - a loud one for attraction, a quieter one for courtship and a stucatto one during mating. 

They can be hard to spot because they are well camouflaged amongst dry grasses and heather, and on warm afternoons their -leap-flutter-glide escape technique can make them hard to catch.

Grasshoppers hatch from overwintering eggs as a tiny worm-like organism that then undergoes four moults as the nymph grows. This is a meadow grasshopper in the  penultimate instar before becoming an adult - it still has wing stubs but these will reach full size during the next moult. 

This female, sitting in the sun amongst bell heather, has lost her hind leg on the left-hand side. Nymphs in early instars can regenerate lost legs but this one must have lost the limb after becoming an adult, perhaps to escape the grip of a bird's beak.

Surprisingly, there are documented instances of grasshoppers that have lost a hind leg being able to stridulate and respond to a mate's song with the remaining limb. The impediment must make for lop-sided leaps though!

Sunday, July 16, 2017

cocksfoot vivipary

Cock'sfoot grass Dactylis glomerata sometimes exhibits unusual reproductive behaviour, known as vivipary.

This is a normal inflorescence, with florets that will produce seeds after pollination ....

..... and this is an abnormal inflorescence that I found a few days ago, where florets have started to form but have no stamens, stigma or ovary and the bracts that surround these structures have become leafy.

This viviparous behaviour is commonest in late-flowering plants and what has happened is that during their development the flowers have become leafy vegetative structures. 

The assumption is that these will eventually drop off, form roots in contact with the soil and grow into new clonal plants that are identical to the parent. 

I've never sen any evidence that these leafy structures are really capable of rooting and forming new plants, so ....

..... I'm keeping a close eye on them to see if it really happens. So far, after four days, those leafy bracts are growing, but so far no sign of any roots....