Car Park Lichens

Two species of lichens are thriving on the trunks of trees in the Asda supermarket car park in Dewsbury but nationally, as sulphur dioxide levels decrease, one of them appears to be gaining ground while the other is becoming rarer.

The yellow lichen with the pale-rimmed orange apothecia (the fruiting bodies of the lichen) is Xanthoria polycarpa, which has spread as levels of sulphur dioxide in the atmosphere decrease.

It’s common on the coast but in urban settings you’ll often find it on twigs, fences and even on painted signs. It can tolerate high levels of nutrients and nitrogen, so it’s common around farms.

What is the source of nutrients or nitrogen here? Do these trees serve as starling roosts or, here in the middle of a car park, does the nitrogen come from vehicle exhausts?

The majority of lichens don’t have common names but the Latin name often includes a succinct description of the species. The genus name Xanthoria means ‘golden yellow’ while the species name polycarpa refers to its many fruiting bodies.

Acid Rain

Between the splodges of yellow, a grey-green lichen, Hypogymnia physodes, covers most of the bark. It grows in similar situations to the Xanthoria and tolerates acidic conditions but, nationally, this lichen has declined as air quality has improved. The introduction of smokeless zones and the phasing out of coal-fired power stations has resulted in less sulphur dioxide in the atmosphere and less acid rain.

It’s only in unpolluted sites that this lichen will produce fruiting bodies; there are three or four of them in my photograph above: red-brown discs on short stalks.

This lichen might be thriving here because it’s growing on the bark of a flowering cherry: cherry bark is highly acidic and in a dried, powdered form, has been used  for medicinal purposes. The horizontal linear scar, visible amongst the lichens on my photograph, is characteristic of cherry.

The ‘Naked-below Bellows-like’ Lichen

The genus name of this lichen, Hypogymnia, means ‘naked below’ and refers to this lichen having no rootlike growths – rhizinae – on its undersurface.

Bellows from ‘Theatrum instrumentorum et machinarum’, 1582

The species name, physodes, means ‘bellows-like’ and I guess this refers to the lobes along the fringes of the lichen which are shaped like a pair of bellows.

In places the fan-like margins appear to be sprinkled with flour. These are described as farinose soredia. Farinose means ‘flour-like’. The soredia produce powdery granules which contain the fungal and algal cells of the lichen; these become detached and can grow into new lichens.

Leaf-like Lichens

Both these lichens are foliose, which means they can easily be detached from the surface they are growing on. Other lichens can be crustose and can’t easily be detached or fruticose: bushy.

Lichens, an Illustrated Guide

Coming across these in the Asda car park in Dewsbury gives me a chance to test out my new lichen field guides. 

The first one that I reach for is the Field Studies Council’s Guide to common urban lichens 1 (on trees and wood). There aren’t many yellow lichens to choose from, so I soon narrow it down to Xanthoria polycarpa, then, taking a good look at my macro photographs of the grey-green lichen, I immediately pick out Hypogymnia physodes from the chart. I need illustrations; I’m not methodical enough to work my way through a key to identify a species.

There’s a brief summary of key features and habitat in the symbols and the tables included in the FSC guide, but it’s useful, now that I’ve got a name to look it up in an index and to go for the more detailed description and notes on distribution in Lichens, An Illustrated Guide to the British and Irish Species, by Frank S. Dobson, which has just been republished in a revised and updated edition.

There are six FSC guides to lichens in particular habitats – such as churchyards, rocky shores and moorland – so if you’re in one of those habitats it’s easier to have the few dozen of the species you’re most likely to come across to choose from, rather than trying to find it amongst the one thousand plus lichens in Frank Dobson’s book. The two publications work well together.

I already had five field guides on my bookshelves which include a selection of lichens but only one of them, The Observer’s Book of Lichens, briefly mentions the particular Xanthoria that I’ve photographed, but it isn’t illustrated and there isn’t enough of a description to enable me to identify it.

If you’re interested in lichens, I’d say it’s worth investing in these two publications (below). I went for the hardback and I’m pleased to say that it’s been given a binding that stays open when you put it down on the desk, which is so useful when you’re looking something up!

Links

FSC Wildlife Pack 20: Lichens at NHBS (Natural History Book Service)

Lichens: An Illustrated Guide to the British and Irish Species at NHBS

Living Room

The armchair, at Barbara’s brother John’s, makes a laid-back still life subject with its generous proportions and its rumpled cushions.

His Sony stereo, with its antenna, eye-like twin knobs and gaping mouth, looks like the head of a robot from an animated movie.

Peace Lily

John’s living room even gives me a chance to sketch some botanical details; there’s a Peace Lily, Spathiphyllum, on the table by the window.

The cluster of small conical flowers, arranged spirally around the spadix appear to be all female.

The Peace Lily, also known as the Sail Plant, is a member of the Araceae family, the Arums, members of which are mainly tropical. There are only two British species: Cuckoo-pint and Sweet-flag.

 

Getting it in Proportion

Sitting in the dentist’s waiting room, looking up Queen Street, I’m attempting to draw the spire of St Peter and St Leonard’s Church, Horbury.

The proportions are so subtle; the tower’s structure reminds me of a four-stage Saturn rocket, about to soar skywards but it might so easily, with the addition of an extra foot or so of girth, start to appear crushingly earthbound or, conversely, if too slender, become too spindly and emaciated to inspire confidence.

It’s the same with the individual pillars: there’s such a slim ‘Goldilocks zone’ between undernourished and elephantine. I think that he got it just right.

The architect, John Carr(1723-1807), started his career working the stone in local quarries. As far as I know, he never had any formal training in architecture, nor did he ever make the Grand Tour, to absorb the classical influence of Italy but as bridge surveyor to the West Riding of Yorkshire, he had an eye for structure.

I walked past the church every day when I attended St Peter’s Junior School, which in those days stood close to where the dentist’s stands today. As I looked up at that wedding cake of a spire, so unlike anything else in Horbury, I’d imagine the kind of character that might be living in there, in the pilastered penthouse apartment above the rusticated clock section. Shutters and a the mini-balcony made me think of Spain or Mexico, so a mantillared señorita or a caballero.

The rotunda of columns could be a home for a minor Greek deity.

The Long Causeway

The steady incline of the Long Causeway to Pinderfields Hospital takes you from the Victorian terraces of College Grove, alongside ivy-covered limes and sycamores at the edge of a playing field and some small shrubby gardens.

Black-headed gulls gather on the football pitch; blackbirds perch in the shrubs and house sparrows bicker in the hedges, gathering around a fatball feeder. There are plenty of berries on the ivy but they have yet to ripen.

We’re surprised how many birds are making use of this slender green corridor. A nuthatch flies down to the footpath in front of us next to a hawthorn hedge. Long-tailed tits and blue tits check out the overhanging branches. Collared doves are calling; chaffinches give a flash of white wing-bars as they fly up into the hedges.

A Strand of Woodland

clouds

Towering cumulonimbus over Smithy Brook valley, white against a blue sky in the morning sun.

Until a few years ago there were twin filling stations at the traffic lights at Shaw Cross but now one of them has closed and it’s surprising how soon the forecourt has reverted to a woodland glade.

Even the bund across its former entrance has already been colonised by sycamore saplings and buddleia bushes, in contrast to the still fresh-looking road markings on the stub of the entrance drive.

 

 

Beyond the Edge

Birstall

Birstall Retail Park: Beyond the stores you glimpse belts of trees interspersed by hillside meadows. The nearby M62 is out of the sight, if not quite out of earshot. This is such a contrast to when we first came here (see link below), when old colliery spoil heaps to the east were being used as a municipal rubbish dump prior to landscaping the whole area.

Even the car park itself holds some attractions for the local birds. A magpie scouts around beneath a shrub, a sparrow closely inspects the links of a chain, a crow surveys the scene from a lamp-post, a wood pigeon flies over.

Trees behind the Home Sense store
Trees behind the Home Sense store.

Daisy, sowthistle, willowherb, creeping buttercup and black medick are in flower on the verges. Leafy backwaters aren’t far away beyond the stores.

With a hour to spare before the film, we take a walk around the Showcase cinema car park. Beyond the steep grass verge at the bottom end of the car park there’s a steep valley where alders, willows and giant hogweed grow beside a storm channel which is currently running dry.

A chiff chaff is singing and we hear another warbler – a bubbly song – which we identify as garden warbler. This deciduous woodland with dense undergrowth is the right habitat for it.

  • Looking east towards Bruntcliffe
lapwings
One of my early images for my online nature diary, drawn in pen but coloured on the computer in an early version of Photoshop in a limited palette to save bandwidth which was very limited in the days of dial-up connections.

Link: Lapwings over Ikea, my Wild West Yorkshire nature diary for Tuesday 1 December 1998.

Town Hall Pigeons

town pigeonpigeon9.20 a.m., Market Place, Ossett, 52°F, 13°C: A town pigeon perches on the antenna on the town hall roof then flies off in a stiff winged display flight. A stubble of rush-like spikes prevents these feral pigeons, descendants of the rock dove, from using sills, mouldings and cupolas as cliff ledges but the strings of Christmas lights still festooned across the facade provide an alternative perch. One has found a niche on a jutting corner.

elder on town hall roofpigeonIt’s not much more than a year since the building was given a major restoration but already two elders have sprouted and are blossoming in crevices in the stonework.

A black-headed gulls flies over and a swift soars around hawking for insects.

Motorway Services

buzzardrookA buzzard circles near Woolley Edge Services; by the picnic benches rooks gather crop-fulls of scraps.

Slip road at the services
Slip road at the services

Calling at a motorway services when we live just five miles away, I feel as if we shouldn’t really be here but we’re meeting with an old friend and her husband who are taking a break here on their journey north.

Bullcliffe Woods, Denby Dale Road.
Bullcliffe Woods, Denby Dale Road.

Driving along some roads in the district, I feel as if every last patch of ground is being built on but heading out this way, I’m astonished at how much countryside we’ve managed to hold on to and how beautiful it looks in the late afternoon sun as woods and hedges burst into fresh leaf and blossom.

Motorway Corridor

motorway embankmentgullOn our morning errands, we take a break at Starbuck’s, Calder Park, next to junction 39 of the M1 motorway. We’re on the verge of spring but in the view from our table the only area of green is winter wheat on the far side of the Calder valley at Lupset.

pegeonBlack-headed gulls, now with neat chocolate brown masks, flap and glide in random search mode above the car park. A town pigeon zooms off on more urgent business.

Peregrine on the Spire

Wakefield Cathedral spire is 247 feet high. Whenever I try to picture a thousand feet, I think of four Wakefield Cathedral towers.
Wakefield Cathedral spire is 247 feet high. Whenever I try to picture a thousand feet, I think of four Wakefield Cathedral towers.

peregrine11.10 a.m., 49ºF, 9ºC, Wakefield Cathedral; A flock of  town pigeons circles and chacking jackdaws return to the belfry ia the louvred shutters, unperturbed by the presence of a peregrine preening on a crocket, halfway up the north-east side of the spire.

It’s wonderful to be able to sit on a bench in the precinct and sketch a peregrine. jackdawsWhen I started birdwatching in the late 1960s and early 1970s, the first peregrines that I saw were in a remote glen in Scotland and on the far south-west corner of Wales, on the Pembrokeshire coast.

Nest platform attached to crenelations.
Nest platform attached to crenelations.

Over much of the country they had been wiped out through partly through persecution but probably more because of pesticide residues in their prey species, which caused a thinning of the shells of their eggs.

Link: Wakefield Peregrines