A Tree-spotter's Guide to Buds: part 1

A beech Fagus sylvatica bud. It always seems to me that buds are under-appreciated natural objects, not just because of their inherent beauty but because that explosion of greenery that we call spring is already pre-packaged inside, protected by bud scales but ready to unfold just as soon as a winter's chill breaks the bud's dormancy.

Charcoal-black ash Fraxinus excelsior buds on grey twigs are unmistakeable. Some buds will burst to reveal a mass of crimson stamens in early spring, others will burst much later to unfurl their foliage. Ash is always the last native tree to come into leaf in Britain.

Hazel Corylus avellana buds, with next year's catkins already formed and ready to elongate and shed pollen next February. Hazel twigs have bristly hairs on their surface. The leaves only unfurl after the catkins have shed their pollen, so as not to inhibit the flow of airborne pollen.

These are the distinctive winged fruits of hornbeam Carpinus betulinus, that cling to the twigs long after leaf fall. You can just see one of the small brown nuts attached to one of the bracts, bottom right.....

... and these are hornbeam buds, which are not quite so distinctive.

A sycamore Acer pseudoplatanus bud, which is particularly attractive in spring when it swells, elongates and in many trees becomes flushed with purple pigments.

And finally, a horse chestnut Aesculus hippocastanum 'sticky bud', with the horse shoe-shaped scar of one of last summer's leaf stalks. For generations of children (me included) who went to rural schools that had a 'nature table', the annual ritual of cutting these buds in early spring and watching them unfold in a jam-jar of water was an annual, memorable ritual that became an enduring totem of spring. For a close look at the marvel of microscopic packaging inside one of these buds, hop over to http://beyondthehumaneye.blogspot.com/2009/11/marvel-of-miniaturisation.html

For part 2 see http://cabinetofcuriosities-greenfingers.blogspot.com/2009/12/tree-spotters-guide-to-buds-part-2.html

For a Tree-Spotter's Guide to Fruits and Seeds, visit http://cabinetofcuriosities-greenfingers.blogspot.com/2010/10/tree-spotters-guide-to-fruits-and-seeds.html

For more posts on tree ID click here

Wall ferns

Three tough fern species that remain green throughout the winter and survive all-year-round in a very inhospitable habitat. First up, wall rue (Asplenium ruta-muraria) thrives in the mortar of old walls and walls made of limestone. There are often fine displays on the shady side of churchyard walls and it often turns up on old masonry in the heart of cities.

 

Maidenhair spleenwort (Asplenium trichomanes) is an exceptionally graceful species and is also a lime-lover, so thrives in crumbling mortar wherever there is some shade and humidity.

Polypody fern (Polypodium vulgare) is an epiphyte – a plant that grows on other plants – and its natural habitat is on moss-covered branches of trees but in Weardale it often makes itself at home in between the capstones of drystone walls. It’s an evergreen fern and if you turn the fronds over even this late in the year you’ll often get a surprise – bright yellow clusters of sporangia on the underside of the fronds.

For a closer look at these hop over to http://beyondthehumaneye.blogspot.com/2009/11/polypody-fern-with-golden-sporangia.html

Is the Only Good Slug a Dead Slug?

Even the most ecologically-orientated gardeners sometimes harbour murderous intentions towards slugs. When they devastate our crops we might spurn slug pellets in favour of beer traps, parasitic nematode worms that eat them alive or simply crushing them under foot - but do all slug species in gardens deserve to die? Occasionally I read claims that there are good slugs and bad slugs, and it’s certainly the case that the smaller, most numerous species do the most damage to vulnerable garden plants. The Little book of Slugs , published by the Centre for Alternative Technology, nominates the field slug (Deroceras reticulatum), the keeled slug (Milax budapestensis), the garden slug (Arion hortensis) and the black slug (Arion ater) as the worst offenders but from time to time I read claims that some species are harmless to garden plants. How true these claims are is open to question - so much of what’s printed in wildlife gardening books seems to be simply copied uncritically from older sources that may well have been wrong – but next spring I plan to do some tests of my own to see if there is any slug species that can be trusted to spend the night in a plot of young, succulent lettuce plants. The most likely ‘good slug’ seems to be the great grey or leopard slug Limax maximus – like this one (above) that’s spending winter under loose bark on an old log in my garden. Edward Step FLS, in his book Shell Life: An Introduction to the British Mollusca, published in the early years of the 20th. century, ventured the opinion that this species “declines all foods containing chlorophyll” but was particularly partial to “kitchen garbage that is not green, such as fat, bread, meat scraps and milk”. More gruesomely, he found that this species was a cannibal, eating the remains of fellow slugs that he’d killed after finding them in milk jugs in his kitchen. Whatever the great grey’s taste in food, it certainly has some very exotic mating habits which you can watch at

http://www.youtube.com/watch?v=GSW9kWIRCOQ

Harlequin II: the nightmare continues.......

It turns out that the harlequin ladybird (widely tipped to devastate our native ladybird population) that I reported in my last post has accomplices. Nyctalus (from http://standandstare-nyctalus.blogspot.com/) and I found more in the same place today, including this multispotted morph of this highly variable species, and – much more interestingly – a fully developed larva that had anchored itself to an ivy leaf by its tail and was about to pupate. Presumable it will overwinter as a pupa and hatch as an adult next spring, but the fact that the species is breeding so late in the season up here in the North is quite remarkable. I wonder, incidentally, whether this species is attracted to ivy, given this plant’s attraction for other insects in autumn, which would be easy prey for a lurking harlequin ladybird while they are preoccupied with nectar and pollen.....

Harlequin ladybird

Had my first sighting of what I believe was a harlequin ladybird Harmonia axyridis yesterday, when I found it feeding on ivy flowers near the entrance to Durham University Botanic Garden. It matches the published descriptions and photographs, although the legs are usually (but not always) brown, whereas in this specimen they are almost black. It has already been recorded in Durham and further North (see http://www.harlequin-survey.org/images/maps/harlequin_years_20July09.jpg) but this is the first that I’ve encountered. It seemed to be nibbling away harmlessly at the nectar on the surface of an ivy flower, but maybe it was just lurking and waiting to do something unspeakable to a visiting native ladybird species....... current opinion is that it could have a devastating effect on our insect fauna as it becomes more widespread - see http://www.ceh.ac.uk/news/news_archive/2009_news_item_28.html. I'll certainly be keeping a lookout for it next year. The wing colour patterns on the harlequin ladybird are astonishingly varied (see http://www.harlequin-survey.org/recognition_and_distinction.htm#).

Deer at Dawn

The fog hadn’t long been cleared by the rising sun and a stiff breeze when we can face-to-face with this roe deer as we rounded a bend in a footpath near Wolsingham in Weardale. It’s hard to tell which of us was more surprised but what is certain is that I was a bit slow off the mark, so all I got was this picture of it bounding off, flashing its distinctive alarm signal – the heart-shaped patch of white hairs on its rump. I guess it didn’t smell or hear us approaching, as we were downwind and the sound of wind through the autumn leaves drowned out our footfall.

A little later we encountered this doe and her fawn on the edge of a field and this time we weren’t spotted until we’d had a good look at them grazing in the early morning sun.

This fawn would have been born last spring and will stay with its mother through the winter.

Eventually they picked up our scent, and were gone in an instant