9 August 2011 OS Explorer 181 Chiltern Hills North
Length: All day (or two hours if visiting College Lake
The full walk covers a miscellany of plants, but the main interest is at the College Lake Nature Reserve of the Berks, Bucks and Oxon Wildlife Trust. The rest of the walk is rather sparse between points of botanical interest, generally easy with no significant hills, but one unpleasant 1-kilometre section of road-walking. Some may prefer just to spend a couple of hours at College Lake
We parked initially at College Lake Canada
College Lake & visitor centre
Abandoned quarry machinery
We turned right along the main path, past a small bush of orange-ball tree Buddleja globosa that has yellow flowers in globular clusters, the distinctive relative of the common buddleia. Along the side of the path is much blue fleabane Erigeron acer.
Blue fleabane
On a fence post we saw a bush-cricket, the long-winged conehead Conocephalus discolor. This was until very recently confined to warm places on the south coast, but has recently spread northwards with a changing climate, although it is still not often encountered in this area.
Long-winged conehead
At the first fork we took the track on the left down towards the lake. The banks on both sides have proliferating clumps of dragon’s-teeth Tetragonolobus maritimus, now showing both flowers and the large seed-pods (“teeth”). This plant only exists otherwise in Bucks at Fingest, where it has been established for a very long time (see the walk of 28 June 2011). It was presumably introduced at College Lake
Dragon’s-teeth
Amongst the clumps of dragon’s-teeth at present are the more usual chalk flowers of yellowwort Blackstonia perfoliata and common centaury Centaurium erythraea.
Down by the lake-shore were taller plants like vervain Verbena officinalis, purple loosestrife Lythrum salicaria, water-mint Mentha aquatica, gipsywort Lycopus europaea, false fox-sedge Carex otrubae and fruiting-spikes of common spotted orchid Dactylorhiza fuchsii, along with plenty of young frogs and dragonflies, of which common blue damselflies Enallagma cyathigerum were particularly abundant.
Common blue damselfly (male)
At one spot there was a marsh with a patch of New Zealand
Ploughman’s spikenard
Just through a gate after a path to the upper track were several specimens of a strange thistle that had very tall ridged cottony stems with few branches and only vestigial stem-leaves, at first sight like a knapweed. This turned out, surprisingly, to be tuberous thistle Cirsium tuberosum, very far from its normal haunt in the south-west. We had to be careful that it was not the form of dwarf thistle that has a stem, but it was too tall for that and the rosette leaves were differently cut with soft spines, not the sharp needles of the commoner plant. This again must have been deliberately introduced, although why so far from its normal range it is difficult to understand. Nevertheless it provides people who would normally have no chance of seeing this very rare and unusual flower with a great opportunity.
Tuberous thistle
This lower path eventually bends round and turns back south along the upper track, which is grassier and has a typical chalk flora and fauna of burnet-saxifrage Pimpinella saxifraga, a helleborine in seed, chalk knapweed Centaurea debauxii and common blue butterfly. On the left side of this path is an arable area sown to wheat and used to conserve a large number of endangered arable annual plants (“cornfield weeds”). Many of these are now difficult to find anywhere in the wild. Just after this field is a grassy area used for educational purposes. Turning into this area and walking back we came to a gate providing entry into the arable land. With so many interesting species it took us quite a while to track down and identify most of them. At this time of the year most are in seed, although occasional later flowers could still be found. While this makes them less conspicuous it is more helpful for identification, especially of the umbellifers. Here we saw: bright blue cornflower Centaurea cyanus still in flower, the exotic flower-spikes of field cow-wheat Melampyrum arvense almost all in seed, corn-cockle Agrostemma githago in seed, pheasant’s-eye Adonis annua, corn parsley Petroselinum segetum, knotted hedge-parsley Torilis nodosa, spreading hedge-parsley Torilis arvensis, corn chamomile in seed Anthemis arvensis, slender tare Vicia parviflora and wild candytuft Iberis amara; plus more common species like dwarf and sun spurges Euphorbia exigua & helioscopa, hop trefoil Trifolium campestre, field madder Sherardia arvensis, field pansy Viola arvensis, common and long-headed poppy Papaver rhoeas & dubium, black medick Medicago lupulina, field bindweed Convolvulus arvensis, bristly oxtongue Picris echioides and fool’s parsley Aethusa cynapium.
Knotted hedge-parsley in fruit & corn parsley
Cornflower
Slender tare in fruit
Pheasant’s-eye
Wild candytuft
Corn chamomile
Spreading hedge-parsley
Field cow-wheat
Dwarf spurge, fool’s parsley & black medick
With time getting on we left this abundant display and continued along the track back to the visitor centre, past catmint Nepeta cataria on the left-hand side, the uncommon true native plant with pink-spotted white flowers, not the blue garden escape. It has a very unpleasant smell.
Catmint
We spent a couple of hours at College Lake Grand Union Canal
GUC lock at junction with Wendover Arm
In occasional pools on the side of the towpath opposite the canal there were some water-plants, mostly water-cress Nasturtium sp and bulrush Typha latifolia, but in places including orange balsam Impatiens capensis and flowering rush Butomus umbellatus.
Flowering rush
Eventually the path continues along a narrow segment of land separating the canal from Startops End Reservoir, where we could see great crested grebes. At Startops End itself a road crosses and here we crossed to the towpath on the other side of the canal in order, when we got to the junction with the Aylesbury Arm we could continue northwards along the main canal. The vegetation was still sparse, although we passed a solitary plant of borage Borago officinalis, probably a survivor from one of the little gardens many of the barge-owners create on the banks. At the canal junction was a wide pool where at least there was a little more space for birds like moorhen, mallard and mute swan. Our purpose in walking along the canal through Startops End was to try to find evidence of the rare grass-wrack pondweed Potamogeton compressus recorded from here, but there was hardly any waterweed at all visible from the bank and the water very cloudy. While we cannot rule out the possibility that it might survive somewhere in the canal, we were rather doubtful in view of the huge amount of human traffic.
At the next road-bridge the towpath changes to the left bank once more, but otherwise continues in much the same way, with little to divert us except for swallows, house martins, and the odd brown hawker dragonfly, despite the fact that the surroundings were now rural fields. When we approached a few houses on the opposite side, just before reaching the Cheddington road, on that same side we could see monkey flower Mimulus guttatus along a short stand of surviving waterside plants of purple loosestrife, reeds, etc. The canal passes under the Cheddington road and we left the towpath just before the bridge and gained the road itself through a car-park. We turned right at the road and then took the first lane on the left, just after a caravan-site, past hedgerow cranesbill Geranium pyrenaicum on the corner.
This lane leads under a railway and then towards Pitstone. This name is Anglo-Saxon derived from “Picel’s” (man’s name) and “thorn”, referring generally to hawthorn. Certainly the hedges along here are predominated by hawthorns Crataegus monogyna and C. laevigata even today, although this is of course not unusual.
Hawthorn, Pitstone
Midland hawthorn, Pitstone
The other major hedgerow constituent is damson Prunus domestica ssp insititia, which dominates much of the walk along the edge of Pitstone, where there used to be many orchards.
Damsons, Pitstone
As we reached Pitstone we turned left again along Chequers Lane, at the end of which the way continues as a footpath alongside the edge of the village. This passes through one old orchard where there appeared to be no old trees left but a virtual thicket of young damsons spreading everywhere, the fruit as bitter as sloes. On reaching a crossing path we turned right to the road along the south side of Pitstone, where we turned right past a school. This brought us to the centre of the village of Ivinghoe , with the Church of StMary Virgin
After lunch we searched the churchyard across the road for yellow chamomile Anthemis tinctoria reportedly well-naturalised here, but there was none to be found in a very manicured cemetery, and only yellow corydalis Pseudofumaria lutea growing freely on the walls with black spleenwort Asplenium adiantum-nigrum and wall-rue A. ruta-muraria.
Yellow corydalis on churchyard wall
Given this disappointment others may prefer to shorten the walk by directly going to Cheddington after leaving the canal, as we now had to retrace our steps past Pitstone and continue on to Cheddington ourselves, there being a pavement beside the road. To our left was a view of Southend Hill, over which we were to walk after Cheddington.
Southend Hill from Pitstone-Cheddington road
As we entered the village there was a pub called the Old Swan on the left which looked like a decent alternative lunch spot for those not including Pitstone and Ivinghoe. Just after this a footpath comes off left along The Slipe and then along the edge of houses until it goes along a boundary between cornfields between Westend and Southend Hills, chalk outliers of the Chilterns. The approach is very gently uphill, but the descent to the SW is slightly steeper.
Westend Hill cornfields
Towards the bottom a wide open private track goes off to the right towards Westend Hill (a “local landscape area”) and we were pleased to see knotted hedge-parsley and dwarf spurge at the edge of the corn along here, two at least of the arable annuals we saw at College Lake that have survived the onslaught of modern agriculture here.
Knotted hedge-parsley, Westend Hill
The field edge also had hedgerow cranesbill and a patch of canary-grass Phalaris canariensis that is presumably a survival from grain brought in for pheasants. The crops themselves are largely devoid of “extraneous” plants, apart from the ubiquitous fool’s parsley. Further west is Cheddington Pit, surrounded by scrub, and remains of Iron Age lynchets. The chalk-pit is sheltered and supports a good chalk flora, including many Chiltern gentians Gentianella germanica, but there is currently no access.
Continuing the footpath SW we reached a stream alongside a “disused camp” which is now used as industrial premises. The path continues between a fence and the stream and is dark and overgrown, along with refuse coming from the dump-site. We had to cut through some bramble and at one point had to shift a large pile of wooden pallets that had toppled over the fence across the path and into the stream! Unfortunately there is no alternative path to this, which carries on for 600 metres. It ends in the road from Cheddington to Long Marston where we had to turn left towards the latter. Again this is not pleasant, as there is no walkable verge. The road is long and straight, which on the positive side means that traffic gets a good view of walkers, but on the negative side means that vehicles are moving very fast indeed. The only relief was finding a small patch of stone parsley Sison amomum on the verge at one point - particularly interesting to be able to compare this with the similar-looking corn parsley we had seen at College Lake
After over a kilometre we arrived in Long Marston, continued across the crossroads, and turned left along a footpath. There are black poplars Populus nigra here and more to be seen on the rest of this path, which took us to the Aylesbury Arm of the Grand Union Canal
Black poplar with leaf-stalk galls
After emerging from between two close hedges the path enters a cornfield where, apart from more fool’s parsley and dwarf spurge there was an abundance of both fluellens Kickxia elatine and spuria. Some of the leaves were mined by the agromyzid fly Chromatomyia horticola.
Round-leaved fluellen
Sharp-leaved fluellen with leaf-mines
After several gates we passed through a kissing gate by a large old black poplar and then followed a stream through scrub where there were several more of these impressive trees.
Black poplar trunk
The path emerges to cross a road to carry on through two more wide fields, along a route which we walked early in the year (see 22 March, Wilstone to Aston Clinton) to see the black poplars in flower. At a third triangular field it is important to keep along the left-hand hedge in order to emerge at the canal where there is a lock and a bridge to cross to the towpath on the other side.
Here we turned left to follow the canal all the way to its junction with the main canal at Startops End. In brickwork by locks along here grew London bur-marigold Bidens connata, which we had earlier seen much further north along the Grand Union at Milton Keynes (see post for 2 August 2011), celery-leaved buttercup Ranunculus sceleratus, marsh yellow-cress Rorippa palustris and jointed rush Juncus articulatus.
London bur-marigold
Celery-leaved buttercup
Dragonflies included migrant hawker and banded demoiselle.
Migrant hawker (female)
Banded demoiselle (male)
Waterside plants were more vigorous along here than along the main canal, with purple loosestrife, wild angelica Angelica sylvestris (with leaf mines of the agromyzid fly Phytomyza angelicae), reed canary-grass Phalaris arundinacea, reed sweet-grass Glyceria maxima, water dock Rumex hydrolapathum and even amphibious bistort Persicaria amphibia extending its leaves and flowers further into the water.
Wild angelica
Amphibious bistort
From the water itself we rescued a fragment of hairlike pondweed Potamogeton trichoides, far more common than the compressus we had earlier sought. There were also grey wagtails to be seen. The hedge on the right contained large-fruited hawthorns, some of which were Midland hawthorn, Crataegus laevigata and others the hybrid with common hawthorn C. x media.
At the canal junction the path continues to the bridge at Startops End where we had initially crossed to the other side. We now continued to Bulbourne, disappointed that the large conspicuous yellow flowers on tall clumps of corn sow-thistle Sonchus arvensis that we had seen on the way out had now closed up with the declining sun and were much less impressive!
No comments:
Post a Comment