Buckinghamshire: West of Turville: Chiltern Gentian & Arable Annuals

16 August 2011                     OS Explorer 171 Chiltern Hills West

Length: All day (but quite a saunter)

The Chiltern gentian Gentianella germanica was selected as the County Flower for Buckinghamshire in a recent Plantlife vote.  As its name suggests it is largely confined to the Chilterns in this country, and this walk and several succeeding ones attempt to visit some of the best spots to see this flower.  A thorough treatment of this species is McVeigh, Carey & Rich (2005) “Chiltern gentian Gentianella germanica (Willd.) Börner (Gentianaceae) in Britain: distribution and current status”.

We parked along Holloway Lane just east of Northend where a footpath starts at the edge of a wood at SU740922.  This is Swains Wood.  From the starting-point we walked straight downhill through the trees along a wide informal track.  This soon leads to an area of chalk grassland which is managed by Berks, Bucks and Oxon Wildlife Trust (BBOWT) in agreement with the owner.  A permit is needed from BBOWT to enter.

Swains Wood grassland

As well as the usual chalk grassland flowers like wild basil Clinopodium vulgare, marjoram Origanum vulgare, burnet saxifrage Pimpinella saxifraga, common centaury Centaurium erythraea, yellowwort Blackstonia perfoliata, dwarf thistle Cirsium acaule, wild thyme Thymus polytrichus, greater knapweed Centaurea scabiosa (leaves with blister-like galls caused by a gall-midge Loewiola centaureae), ploughman’s spikenard Inula conyzae, dewberry Rubus caesius, milkwort Polygala vulgaris, and eyebright Euphrasia nemorosa, and chalk knapweed Centaurea debauxii, we saw large populations of harebell Campanula rotundifolia, carline thistle Carlina vulgaris, rock-rose Helianthemum nummularium, small scabious Scabiosa columbaria, clustered bellflower Campanula glomerata and particularly Chiltern gentian.  

Dwarf thistle

Harebells

Carline thistle

Small scabious

Clustered bellflower

Chiltern gentian, Swains Wood

Blister galls on greater knapweed

The gentians were only just starting to flower and should be good for several weeks yet, although the dark purplish leaves tend to make them obvious even without the reddish-purple flowers whose tube is far longer than the calyx.  Small plants, often with single terminal flowers, were probably annual forms of the same species.  Earlier in the year there had obviously been a good showing of various orchid species judging from the fruiting spikes – we identified three other species in addition to common spotted orchid Dactylorhiza fuchsii.  The round-mouthed snail Pomatias elegans, an indicator of good chalk grassland, was active in the turf still wet from showers the night before, but the cool overcast early morning was not conducive to the appearance of butterflies, another class of wildlife for which the reserve is important.  A galium carpet moth Epirrhoe galiata was, however, disturbed from the undergrowth.

Having admired these floriferous slopes for a while we returned up through the wood to the footpath running east along its edge with Holloway Lane.  The woodland all along here has frequent clumps of spurge-laurel Daphne laureola. 

Spurge-laurel

The figworts Scrophularia nodosa had extensive mines of the agromyzid fly Amauromyza verbasci in some of their leaves.  The lane is obviously ancient and well-named, as it is enclosed in high vertical banks, on top of which are boundary-trees of coppiced hazel Corylus avellana and beech Fagus sylvatica. 

Holloway Lane

Coppiced beech

The wood also has oaks Quercus robur and elms Ulmus glabra, wood millet Milium effusum and wood melick Melica uniflora, with the main ground plant being dog’s mercury Mercurialis perennis.  There is a sprinkling of wood-sorrel Oxalis acetosella and wood-spurge Euphorbia amygdaloides.  Red kites continually mewed in the sky, as they continued to do all day, so numerous have they become since being reintroduced to this area.

The path ends in a track going across and we took this to the left, across the road, over a stile and straight up a field slope (not turning right along a narrow belt of trees beside the road).  This field had been cut although we could still recognise common poppy Papaver rhoeas and scented mayweed Matricaria recutita.  The path continues through a narrow belt of woodland and up another cultivated field with dwarf spurge Euphorbia exigua and wild mignonette Reseda lutea.  This was followed by an uncultivated grass slope (Grays Lane Bank) with generally taller vegetation than in Swains Wood, but still with a rich flora of wild parsnip Pastinaca sativa, rock-rose, clustered bellflower, carline thistle, Chiltern gentian, eyebright, large thyme Thymus pulegioides, fairy flax Linum catharticum, autumn hawkbit Leontodon autumnalis, ploughman’s spikenard, common milkwort, and common knapweed Centaurea nigra.  At last a few meadow browns were flying desultorily among the flowers.

Grays Lane Bank

Chiltern gentian, Grays Lane Bank

We were soon through this small but valuable chalk bank and into another hollow way (Grays Lane) through a belt of beech woodland with more dog’s mercury, spurge-laurel and a little gooseberry Ribes uva-crispa. 

Grays Lane bridleway

The path leads into the surfaced drive of a house, with a large stand of blackcurrant Ribes nigrum on the left and wood barley Hordelymus europaeus on the right. 

Wood barley

This soon becomes a small lane to Helicopter Farm, where a footpath starts on the right.  We turned along this path, and kept bearing right to return southwards again through a rather dull woodland of beech and other trees with no botanical interest (Parsonage Wood).  The wood slopes steeply to the right and several beech trees had fallen up the slope, their root-plate exposed, but still with some roots in the ground, so that new branches had grown vertically from the trunks and were still flourishing, no doubt a frequent adaptation for a tree that has a shallow root-system and is therefore prone to being toppled by storms. 

Fallen beech growing vertical branches

The path bends to the top of the wood and we continued south here along a path still inside the wood.  A herd of half-a-dozen roe-deer were frightened from the adjoining field by our presence and stampeded across then path in front of us, stopping to stare back at us at the bottom of the slope.

Eventually we reached Ibstone churchyard on our left, which is unfenced from the wood, and walked into there.  While we were here we looked for sowbread Cyclamen hederifolium, supposed to be long established here, but we saw no evidence of it. We might have been just a bit early for its flowering which, as it does so before the leaves appear, would make it impossible to locate.  Nevertheless there was some compensatory interest from a single old yew Taxus baccata, whose hollow bole seemed to have been unfortunately in-filled with concrete!  It had a good girth of just over 6 metres and must be many centuries old.  The only other plants of note here appeared to be dark mullein Verbascum nigrum.  The church of St Nicholas, which is rather small and isolated from the main part of the village, dates back in parts to the early 12^th century.

Ibstone Church

Old yew in churchyard

[Added 25 October 2011: We re-checked Ibstone churchyard today and can confirm that there is no established Cyclamen there anymore.  It is still worth a visit for the old yew tree anyway.  We also found we missed a trick last time: instead of entering the churchyard from the woodland path at the first opportunity, if you go to the far end of the churchyard to where the woodland path turns sharp right, there is a large colony of small teasel Dipsacus pilosus, a plant that seems to be very scarce these days.]

We left the churchyard on the other side by the road, turning left and then immediately right along another sunken lane, leaving by a footpath on the left at the first bend.  This followed the edge of Park Wood, where there was yet more spurge-laurel and through a more open beechwood (than Parsonage Wood above), with much grass growing at ground level around stands of nettle Urtica dioica.  The trees were mostly young and the wood had obviously been cleared and replanted not long ago, hence the greater amount of light (and soil disturbance).  Although still very overcast one speckled wood managed to take wind.  The path eventually turned right to the wood-edge again and then progressed between two fences with the wood on our left and a field of maize on our right.  Along here was a multitude of vervain Verbena officinalis, a plant that seems to be much localised.  On the wood-bank were rock-rose, mouse-ear hawkweed Pilosella officinarum and redcurrant Ribes rubrum.  There were good views down the valley where Turville lies.

View of Turville from Park Wood edge

Rock-rose

At the far corner of the field a stile gave entrance to a scrubby chalk bank with more clustered bellflower and large thyme but no Chiltern gentian.  This led to a long open-access field occupying the steep south-facing slope of Turville (or Cobstone) Hill.  The initial flora was limited, largely dwarf thistle, chalk knapweed, small scabious, (with a small heath appearing, to add to our rather sad butterfly tally) but as we neared the eastern end there was a good deal of Chiltern gentian and carline thistle, rest-harrow Ononis repens, and yellowwort. 

Chalk knapweed

Chiltern gentian, Cobstone Hill

As we reached the footpath descending the far edge of the field we could just see the tops of the sails of Cobstone Windmill just above the brow.  As we descended the path into Turville village, looking back the windmill was now completely visible.  It is a smock mill (formally belonging to the parish of Ibstone) built about 1816 to replace an earlier one and used until 1873, after which it steadily deteriorated until restored by film-stars Hayley Mills and Ray Boulting in 1971 to be used as a private residence, which it remains to this day. 

Cobstone Windmill

The lane into the village had hedgerow cranesbill at the edge. 

Hedgerow cranesbill

Reaching the road there was the Bull and Butcher pub across the road where we could rest for lunch.  This has plenty of outdoor tables for finer days. 

Bull & Butcher

Turville is so quintessentially rural English that it is frequently used in film-making (“Went the Day Well?”) and TV (“The Vicar of Dibley” and many others), while the windmill featured in “Chitty Chitty Bang Bang” and other films.

Turville (pity about the cars)

After refreshment we continued along the road westwards, taking a brief look at the churchyard, where there were a few exotic trees, including what seems to be Malus “John Downie” (see photo).  

Turville Church and Malus “John Downie”

Malus “John Downie”

This church, St Mary, also dates back to the early 12^th century and of course featured prominently in “Vicar of Dibley”.  We turned left along the first footpath/bridleway at the end of the village.  This was a relatively easy slope up beside a cornfield towards the next ridge.  The wheat, as usual, had been sprayed, but at the edge of the crop there were still interesting arable “weeds”, increasing in number as we rose up the slope into chalkier horizons.  There was a lot of corn mint Mentha arvensis, sharp- and round-leaved fluellens Kickxia elatine & spuria, fool’s parsley Aethusa cynapium, and dwarf spurge, with scarlet pimpernel Anagallis arvensis, dark mullein, field pansy Viola arvensis, and field madder Sherardia arvensis. 

Corn mint

Sharp-leaved fluellen

Round-leaved fluellen

When we reached the wood at the top we continued west along the bridleway that follows the edge of the field.  The arable plants were less prominent here, but there was a little small toadflax Cheonorhinum minus. 

At the far corner of the field the bridleway turns into Churchfield Wood and we were now faced with the stiffest climb of the day, straight up a very steep slope through beech, dog’s mercury growing in the lighter patches.  At the top we turned left into another track to Turville Court, where a road begins that takes one on westwards.  Just before a road-junction a path on the right took us into a cultivated field which seemed to be devoted to red clover Trifolium pratense and other plants of disturbed ground.  Amongst the clover and common plants like scentless mayweed Tripleurospermum inodorum, orache Atriplex patula, fat hen Chenopodium album, black nightshade Solanum nigrum and common vetch Vicia sativa, there were more surprising and rare plants like long-headed clover Trifolium incarnatum ssp incarnatum, its dark red heads visible from far away scattered over the field.  As more flowers emerge below the ones that open first, the head lengthens to give it its name. 

Black nightshade

Common vetch

Long-headed clover

Long-headed clover – early flower-head and seed-head

Also here were field woundwort Stachys arvensis, uncommon in this area, the bright blue blooms of cornflower Centaurea cyanus and the now rather rare corn chamomile Anthemis arvensis, stinking chamomile Anthemis cotula, many-seeded goosefoot Chenopodium polyspermum and tall densely-whorled spikes of black bent Agrostis gigantea. 

Cornflower

Corn chamomile

Stinking chamomile

Roesel’s bush-crickets Metrioptera roeselii were abundant amongst the dense vegetation.  Having been rare even in their south coast haunts a couple of decades ago, these crickets have since spread northwards and can now be found in most areas of scrub and coarse vegetation in this area. 

Roesel’s bush-cricket

A stile led into a cow pasture with abundant marsh cudweed Gnaphalium uliginosum which appreciates a regular trampling, and another stile brought us into Turville Heath beside the old red-brick house of Turville Grange (mid 18^th century), which has elaborate wrought-iron gates from about 1907. 

Turville Grange

We turned right to take the track along the NE side of the common, which is mostly trees and bracken Pteridium aquilinum, with a major invasion of Indian balsam Impatiens balsamifera, which seems to have got into most parts of the common.  Although not native it still attracts leaf-mines from an agromyzid fly Phytoliriomyza melampyga.  

Indian balsam on common

This whole area, the common surrounded by well-spaced houses is a Conservation Area for its historic interest (including seven listed buildings) and some of the trees. 

Turville Grange Cottage (early 19^thC) & Rose Cottage (late 18^thC)

On this NE side we passed one large tree of large-leaved lime Tilia platyphyllos, but it was not until we had reached the NW corner of this row of houses that the track bent round to the left and into a grand avenue of planted small-leaved limes Tilia cordata and a few common limes Tilia x europaea, the hybrid between the two. 

Avenue of limes, Turville Heath

Older trees that had been lost had been replaced by young trees of small-leaved lime.  Both small- and large-leaved lime are rare these days in the Chilterns, so although these are obviously planted they are important for conservation.  The small-leaved limes were obvious not only because of their noticeably smaller leaves, but because their flowers and (at this time of the year) their fruits are held erect above the leaves, not pendulous like those of the other two limes.  There must be about 60 lime trees altogether in this long avenue all along the west side of the common.  Another 20 or so border the entrance road to Turville Park (late 17^th century).  The avenues are believed to have been planted in the 1740s by William Perry who lived at Turville Park.  The large-leaved lime had the nail galls of the mite Eriophyes tiliae and the small-leaved limes somewhat shorter and less pointed but similar galls caused by a different mite Aceria acuteangulatus.  Although neither of these two mites feed on the other native lime species, it is interesting that they both occur on the hybrid.  

Small-leaved lime with fruits & galls

Old small-leaved lime tree

Having reached this side-avenue we took a track eastwards across the centre of the common.  There are some old oak trees and silver birch Betula pendula, but there has been a considerable growth of scrub in the last few decades and very little of it is now used as grazing common as it was traditionally, so that despite voluntary management it now looks sadly neglected. 

Oak, Turville Heath

A footpath leaves Turville Heath beside Turville Heath Farm.  This path goes along another sunken way down through Idlecombe Wood, with mostly male fern Dryopteris filix-mas in the damp shade, but also a little lady fern Athyrium filix-femina. 

Lady fern

Below the wood the track proceeds between coppiced hazels with fields each side.  Just after the entrance to Spinney Farm we turned left along the path by Holloway Lane with which we had started the walk.  In these woods large parties of wrens were conspicuous, presumably teenage gangs of this summer’s broods.  Who knows what turf wars were going on!

Buckinghamshire/Hertfordshire: Bulbourne to Ivinghoe

9 August 2011                         OS Explorer 181 Chiltern Hills North

Length: All day (or two hours if visiting College Lake only)

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, the entrance to which is a short distance east of Bulbourne, just over the canal SP934137.  A donation is requested for use of the car park, open from 9.30am.  Entrance to the reserve is through a recently completed visitor centre and café, beyond which is a broad view over the large lakes that comprise most of the reserve.  The reserve was created out of an old chalk pit and the chalk slopes around the lakes are becoming vegetated with a diverse and interesting flora, helped by many introductions.  While the water and marshes have been created for a variety of water-birds and waders, at this time of the year these are of course rather restricted – we saw only mute swans and Canada geese!

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 as a safeguard against the destruction of the original colony, but it has become so rampant it may crowd out other species and threaten higher biodiversity. 

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 pigmyweed Crassula helmsii, an unwelcome introduction probably carried by water-birds.  Chalk cliffs on the other side of the path had fern-grass Catapodium rigidum, ploughman’s spikenard Inula conyzae, and kidney vetch Anthyllis vulneraria with dingy skipper and small heath butterflies.

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

College Lake is towards the “zoo” end of conservation, as it is an artificially created environment, with many deliberate introductions among naturally regenerating chalk grassland and marsh, “show-casing” some of our rare flora, but zoos have important functions, both educational and breeding endangered species.  Exciting as it is to see so many rare species, it does not ultimately compare with the experience of finding them, usually after more effort, in more truly wild habitats – as we were able to do with one of the rare arable annuals above later on in this walk.

We spent a couple of hours at College Lake, and decided that there was not enough time to complete the whole walk before the gates of this reserve would close at 5pm.  We therefore had to move our car and park it in Bulbourne before resuming our route, which proceeds along the left bank of the Grand Union Canal north from Bulbourne.  The canal was very busy with both barges and fishermen, so the banks had little vegetation and the water, frequently dredged, appeared to have little weed, although a few fragments of water-milfoil occasionally floated by.

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 on the right and the Kings Head Inn on the left.  The latter, a hotel rather than a pub, provides good food in a fairly up-market restaurant.

Church of St Mary Virgin, Ivinghoe

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.  This road crosses the county boundary from Bucks into Herts. 

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.  A distinctive twisted gall in the leaf-stalks of these poplars is common and specific to this species, caused by aphids Pemphigus bursarius. 

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!