London: East End Canals

5 September 2014

This trip was almost entirely a replica of the walk for the Botanical Society of the British Isles (BSBI) led by John Swindells on 11 September 2014, ten years ago to the week.  Given that many of the plants in such an urban location are adventives, we felt it would be interesting to see how many could be replicated and what newcomers there might be.

          We began from Mile End tube station, walking north up Grove Road on the east side.  A small concrete wasteland behind railings immediately yielded Annual Mercury Mercurialis annua (a common weed in London), Bilbao's Fleabane Conyza floribunda (which has become almost as common as Guernsey Fleabane Conyza sumatrensis these days), Greater Celandine Chelidonium majus, London Rocket Sisymbrium irio (nowadays rather difficult to find), Red Valerian Valeriana dioica and Buddleia Buddleja davidii, the latter occurring throughout the walk, as it did ten years before. 

Annual mercury

 When we reached the terraced houses we were pleased (and rather surprised) to find that Pink-headed Knotweed Persicaria capitata was still growing in the small concrete front garden of no.36.  Our inspection of this plant brought some unwanted attention from a lady searching the waste-bins along this street, perhaps thinking we had discovered some useful treasure before she could obtain it.  She is probably still mystified by our interest in this plant!  It was presumably a garden escape originally, but has certainly succeeded in becoming well-established, even if it shows no signs of spreading beyond this one site.

Pink-headed Knotweed, Grove Road

 Across the road, at the north end of Mile End Park is a small allotment, the unkempt surrounds of which provided a number of interesting plants.  Chicory Cichorium intybus, Black Horehound Ballota nigra, Bristly Ox-tongue Picris echioides, Fat Hen Chenopodium album, Fennel Foeniculum vulgare and Lucerne Medicago sativa were all recorded ten years ago.  Others not mentioned in the summary of that walk (www.bsbi.org.uk/FieldMeetings2004.pdf) were: Feverfew Tanacetum parthenium, Argentinian vervain Verbena bonariensis (an increasingly common escape, perhaps because it is offered by all the garden centres), Apple- and Pepper-Mints Mentha x villosa & x piperata, and what we assumed at the time to be a Small Teasel Dipsacus pilosus in seed, but on second thoughts may actually have been an escaped Yellow-flowered Teasel D. strigosus, as the native pilosus seems unlikely here.

Lucerne in seed

We continued south through Mile End Park, where there was plenty of rough grassland and more lucerne, fennel and bristly ox-tongue.  Also still here from ten years ago were Hoary Mustard Hirschfeldia incana, Mugwort Artemisia vulgaris and Wild Carrot Daucus carota, plus the hairy form of Black Nightshade Solanum nigrum ssp schultesii (not seen until later in the walk last time) with its commoner subspecies nigrum.  Seeding with meadow flowers in the last decade may have explained the addition now of Greater Knapweed Centaurea scabiosa, Hedgerow cranesbill Geranium pyrenaicum, Lady's Bedstraw Galium verum, and Red Bartsia Odontites verna, but the large stands of Hemlock Conium maculatum were more likely natural colonisation.  There was also Fairy-ring Champignon Marasmius oreades.

Mile End Park

Solanum nigrum schultesii

 Crossing this grassland we reached the banks of the first canal, the Grand Union, which we followed south to its end.  The edge of the canal itself had Gypsywort Lycopus europaeus, Skullcap Scutellaria galericulata, and Beggarticks Bidens frondosa, all of which had been recorded ten years before.  There was also Narrow-leaved Michaelmas-daisy Aster lanceolatus.  On the opposite side were the large leaves of Water Dock Rumex hydrolapathum. 

Common skullcap

Narrow-leaved Michaelmas-daisy

 By the side of the path there were also, as before, Guernsey Fleabane Conyza sumatrensis, lots of Perennial Wall-rocket Diplotaxis tenuifolia, Pellitory-by-the-wall Parietaria judaica and the schultesii form of Black Nightshade.  Other plants here included the Burnet-saxifrage Pimpinella saxifraga, Hoary Plantain Plantago media and Bladder Campion Silene vuylgaris, more familiar in limestone grasslands, plus Pink-sorrel Oxalis articulata and Shaggy Soldier Galinsoga quadriradiata. 

Perennial wall-rocket

 At the base of a tree was a group of Poplar Fieldcap fungi Agrocybe cylindracea, while a conspicuous caddis-fly Mystacides longicornis (with long-antennae, looking more like a longhorn moth) was found resting on canal-side vegetation.

Poplar fieldcap

Mystacides longicornis

 On the earlier trip a strip of long-grass parkland, near where Ben Jonson Road crossed the canal, had yielded a number of plants, but the character of this had changed, there being signs that meadow-flower seed had been applied, with Viper's Bugloss Echium vulgare, Cornflower Centaurea cyanus (seen in 2004 only in Mile End Park), Goat's-rue Galega officinalis, and Musk Mallow Malva moschata now present.  Shaggy inkcaps Coprinus comatus grew here.

Cornflower

Musk mallow

Grand Union Canal & typical ruderal plant habitat.  "R.I.P. Troy Davis" refers to a black person executed in 2011 in Georgia for murder of a policeman, although he always claimed he was innocent and evidence emerged after his sentence that another person had committed the crime.

This isolated chimney beside the Grand Union is apparently just a sewage ventilation shaft

South from here all the way to Limehouse Basin had been very productive in 2004, with 13 further plants being recorded, but the sides of the canal and the tow-path had clearly been tidied up since then and plants were sparse.  Only three of these plants were seen again - Fat Hen, more Black Nightshade ssp schultesii, and Narrow-leaved Ragwort Senecio inaequidens. 

Narrow-leaved ragwort

The paving around the upmarket residences around Limehouse Basin itself had also been rigorously cleaned of plant life and the Prostrate Spurge Euphorbia prostrata that had got a hold here was now gone.  We did, however, see Water Bent Polypogon viridis, present in 2004 a little further along the route.  It was the only plant that seemed to be able to survive the pavement cleaners.

Sterile environment of the Limehouse Basin

From the Basin we followed the Limehouse Cut canal north.  There was abundant Pellitory-by-the-wall on the walls as before, and also Mexican-tea Dysphania (formerly Chenopodium) ambrosioides, Water Bent, and Tall Nightshade Solanum chenopodioides were still present as well.  Both the Mexican-tea and the Tall Nightshade managed to grow from the canal-side brickwork itself.  This stretch had much more vegetation than by the Grand Union and we also recorded the cultivated form of Red Clover Trifolium pratense, Mexican fleabane Erigeron karvinskianus, Water Figwort Scrophularia aquatica, Hemp-agrimony Eupatorium cannabinum, Hemlock Water-dropwort Oenanthe crocata, Tomato Solanum lycopersicum, Dwarf Mallow Malva neglecta, Garden Pansy Viola x wittrockiana, Purple Toadflax Linaria purpurea, Trailing Bellflower Campanula poscharskyana, Round-leaved Cranesbill Geranium rotundifolium, and the wall ferns Black Spleenwort Asplenium adiantum-nigrum, Hart's-tongue A. scolopendrium and Common Polypody Polypodium vulgare.  This made up in quantity, if not in quality, for the plants missing from alongside the Grand Union compared to 2004.

Limehouse Cut

Tall nightshade

Tall nightshade, showing woody stem

Mexican tea

The Limehouse Cut ends at its junction with the Lea Navigation at Bow Locks.  It was here in 2004 that we were able to see together and compare all three Bur-marigolds Bidens spp.  Unfortunately the locks were at this time under reconstruction and there was no access to the area successfully botanised previously, although we could see plenty of plants of Bidens just past here, north along the Lea Navigation.  Near Bow Locks, we were still able to record Fat Duckweed Lemna gibba, as before, but saw no sign of the Water Fern Azolla filiculoides that had previously grown with it.  We also saw Marsh Woundwort Stachys palustris (recorded a little later last time) and Orange Balsam Impatiens capensis, not noted in 2004.  The bur-marigolds gave us a lot of trouble, as all the plants were vegetatively very similar.  London Bur-marigold Bidens connata is supposed to have leaves predominantly less lobed than in Trifid Bur-marigold Bidens tripartita, and Beggarticks should have had more leaves with extra lobes, but all plants were like the normal form of tripartita, although when we examined seeds from various plants beside the Lea Navigation, we found representatives of all three species, as determined by the direction of barbs on them.  It appeared to us that the three species had been subjected to considerable hybridisation that had made them difficult or impossible to tell apart on characters other than the seeds themselves.

London bur-marigold (according to the seeds)

Along the Lea Navigation we not only saw the Fennel, Celery-leaved Buttercup Ranunculus sceleratus, Rigid Hornwort Ceratophyllum demersum, and Large-flowered Waterweed Egeria densa that had been recorded before (although we saw no sign of Danewort Sambucus ebulus or Floating Pennywort Hydrocotyle ranunculoides), but we added many more species to our list, much more Mexican-tea, Perennial Wall-rocket, Shaggy Soldier and Goat's-rue, but also Hop Humulus lupulus, Ivy-leaved Toadflax Cymbalaria muralis, Smooth Sumac Rhus glabra, Gallant Soldier Galinsoga parviflora, Oxford Ragwort Senecio squalidus, Wild Mignonette Reseda lutea, Bouncing Bett Saponaria officinalis flore pleno, Common Evening-primrose Oenothera biennis, Pale Corydalis Pseudofumaria alba, Greater Duckweed Spirodela polyrhiza, South American Waterweed Elodea callitrichoides, and Nuttall's Waterweed E. nuttallii.

Pale corydalis

Three waterweeds - from left: large-flowered, Nuttall's & South American

We stopped off at House Mill Café at Three Mills for a drink and snack.  Beyond here we were close to the Olympic Stadium at Stratford that had been built since 2004 and was now being rebuilt for alternative uses, making the walk rather noisy.  The Anish Kapoor "Orbit" structure was clearly visible.  This towpath was probably on the circuit for tourists in 2012 and it was marked by a huge amount of street art, much of it very impressive.

Oympic stadium under reconstruction & "Orbit"

Lea Navigation & mural by the street artist "Sweet Toof"

Exotic wildlife by the Lea Navigation

Mural on the White Building by the street artist "Ekta Ekta"

At Carpenters Road we turned on to the towpath west along the Hertford Union Canal.  There was more street art along here, compensating for a lack of new plants for a while, but we eventually came across a few small plants of Common Amaranth Amaranthus retroflexus, seen at the same spot ten years ago - we were very surprised to see this usually ephemeral plant again.  We knew it had been near the classic site for the rare Tapegrass Vallisneria spiralis (TQ3602983396, 100m before Grove Road), and we were pleased to see its long strands floating just beneath the surface of the water well out into the canal.  A few strands were near enough for us to check its identity (as there were no flowers).  Also along this part of the canal we saw our third Conyza Canadian Fleabane C. canadensis (the fourth, Argentine C. bonariensis, continues to elude us), Russian Vine Fallopia baldschuanica, Orange Mullein Verbascum phlomoides, Garden Lobelia Lobelia erinus, and, finally, on the balustrade of Grove Road Bridge, Henbit Lamium amplexicaule.  We did not see London Rocket at Bow Wharf as in 2004, but we had already seen it at the beginning of our walk.

Tip of tape-grass frond showing characteristic small teeth at apex only

Beggarticks (as identified from seeds) by Hertford Union

Orange mullein

Garden lobelia by Hertford Union

Henbit on Grove Road Bridge

Mural, Hertford Union Canal

Mural by "Ali Hamish", Hertford Union Canal

Unusual bronze sculpture as street art, by "Jonesey", beside Hertford Union Canal

Hertford Union Canal near the tape-grass site

At Grove Road we walked south to the Ecology Park near Roman Road.  In 2004 we had seen Fringed Water-lily Nymphoides peltata and Lesser Bulrush Typha angustifolia here and both were still evident, the latter quite abundant.  The park had, however, got far more overgrown in the last ten years and there was no sign of Buttonweed Cotula coronopifolia or American Galingale Cyperus eragrostis anymore.  We did see more Celery-leaved Buttercup and a patch of Stone Parsley Sison amomum, and, less pleasingly, plenty of New Zealand Pygmyweed Crassula helmsii.  We also saw Emperor Dragonflies and were able to watch a Brown Rat scuttling around a pond edge and even doing a little swimming. 

Roman Road Ecology Park

Lesser bulrush

We crossed to the nearby towpath of the Grand Union Canal to take this north-west to Bethnal Green (this was not part of the 2004 route).  The canal here was full of moored barges and plants were very scarce, but we did see more Common Amaranth and Rigid Hornwort, plus one final new addition - Common Millet Panicum miliaceum.

Common amaranth

Common millet

We finally turned south down Cambridge Heath Road towards Bethnal Green tube-station, stopping for an evening meal at the excellent restaurant (Corner Room) in the old Town Hall, now a hotel.

London: Thames from Kew to Richmond

29 August 2014

This walk was mainly along the tow-path by south bank of the Thames from Kew to Richmond Lock and back along the north bank, which was partially waterside and partially through streets.  We were right under the flight-path from Heathrow and the conversation-drowning brain-pummelling roar of aeroplanes every few minutes was wearing all day, even blotting out the screams of the Ring-necked Parakeets so well established in this area.

View of Thames from Richmond Lock, with tow-path to Kew to the right

After buying pastries for lunch from a market stall by Kew Gardens tube-station, we started off with a spin around Kew Gardens.  We were too early for the autumn colours of the trees and although the planted borders were very colourful, many outdoor flowers were finished.  The rampant Spreading Yellow-Sorrel Oxalis corniculata gave some brightness to rockeries and bark-mulched soil, where toadstools like ink-caps and Shaggy Parasol Macrolepiota rhacodes ssp bohemica were already beginning to appear.  A few Meadow Saffrons were variously standing or collapsing in the grass.

Spreading yellow-sorrel

Meadow saffron

At any time of the year there are always some trees worth a look.  Near the Palm House we noticed the globular brown fruits of an Asian Pear Pyrus pyrifolia, but resisted sampling them, although supposed to taste like pear and be very juicy.  They are speckled with white lenticels like Sorbus fruits.

Asian pear

In the Mediterranean Garden by King William's Temple two trees stood out for their distinctive bark - Cork Oak Quercus suber with its soft thick cracked variegated bark now unfortunately going out of fashion for corking bottles, and the Cyprus Strawberry-tree Arbutus andrachne with striking red bark peeling in strips.

Cork oak

Cyprus strawberry-tree

Nearby we could not help noticing several Paper Mulberry trees Broussonetia papyrifera, with their attractive globular orange flower-heads and elegant leaves.  The fruit is edible (it is a member of the mulberry family) and the bark was used for paper-making in ancient China.  It is, however, an invasive plant in some tropical areas.

Paper mulberry flowers and leaves

Just west of the Princess of Wales Conservatory is a famous old Ginkgo Ginkgo biloba ("Heritage Tree") with its long pendent branches of leaves descending like a shower, planted in 1762, when Britain declared war on Spain and Rousseau published his "Social Contract".

Old ginkgo bole and leaves

Nearby we stopped to celebrate the birthday of the 200-year-old Corsican Pine planted in 1814, the year when the most famous Corsican, Napoleon Bonaparte, was exiled to Elba.

200-year-old Corsican pine

There is usually some artwork celebrating the world of plants at Kew - on our spring walk here we encountered giant wooden mushrooms.  This time it was trees clothed in knitting patterns and some incongruous sheep.

Leaving by the Elizabeth Gate we walked through Kew Green to the Thames tow-path, walking west, to see if any of the exotics recorded for this stretch of the river remained.  These plants tend to be ephemeral, however, and we did not see the California Brome or the Ball Buddleia we had seen many years ago, nor Fig or Tree-of-heaven, but there were still some plants of interest, despite the vegetation being regularly cut and generally pretty dull.  One speciality of the Thames we were to find, but not until much later.

          Walls had Harts-tongue Asplenium scolopendrium, Black Spleenwort A. adiantum-nigrum, Wall-rue A. ruta-muraria, Polypody Polypodium vulgare, Ivy-leaved Toadflax Cymbalaria muralis, Pellitory-by-the-wall Parietaria judaica, and the lichen Cladonia humilis.

Cladonia humilis

Waterside plants were mainly Gypsywort Lycopus europaeus, Purple Loosestrife Lythrum salicaria, Pendulous Sedge Carex pendula, Wild Angelica Angelica sylvestris, and Water Figwort Scrophularia aquatica, along with some aliens: lots of Indian Balsam Impatiens balsamifera, Orange Balsam I. capensis, and occasional Garden Angelica Angelica archangelica with its thick-winged seeds and greenish, rather than pinkish, flowers.  Common blue damselflies Enallagma cyathigerum were active.

Male common blue damselfly

Wild angelica

Orange and Indian balsams

At this time of the year we are inevitably drawn to the fleabanes.  We identified Canadian Conyza canadensis. Bilbao's C. floribunda and Guernsey C. sumatrensis, but did not see any of the Argentinian with its red-tipped bracts.  Other flowers of the rough grass were Greater Celandine Chelidonium majus, Hedgerow Cranesbill Geranium pyrenaicum, Green Alkanet Pentaglottis sempervivum, Bristly Ox-tongue Picris echioides, Travellers’ Joy Clematis vitalba, Lesser Burdock Arctium minus, Horse-radish Armoracia rusticana, Black Horehound Ballota nigra, Oxford Ragwort Senecio squalidus and Prickly Lettuce Lactuca serriola.  Some of the lesser burdock exhibited an unusual condition of phyllanthy, a proliferation of leaves below the flower-heads - we were not sure whether this was the result of an attack by some virus or just a mechanical response to being severely cut back: the plants in question were all low and close to the ground.  The result was attractive and worthy of becoming a garden cultivar!

Lesser burdock with a proliferation of leaves below the flower-heads

Many of the plants grew on the precipitous stone rampart descending to the river, including many of the fleabanes and clumps of Michaelmas-daisy.  Where we could sample the latter they turned out to be Narrow-leaved Aster lanceolatus.

Narrow-leaved Michaelmas-daisy

Trees along the way included Grey Alder Alnus incana, Turkey Oak Quercus cerrifolia, Hybrid Oak Quercus x rosacea (with mines of the moth Stigmella roborella) and Hybrid Black Poplar Populus x canadensis (which had the distinctive spiral petiole galls of the aphid Pemphigus spyrothecae and the leaf galls caused by the fungus Taphrina populina).

Grey alder

Hybrid oak

Spiral gall on stalk of hybrid black poplar leaf

There were also several fruit-bearing trees of the rarely-seen Black Walnut Juglans nigra, which has more leaflets than the common species, these leaflets being well-toothed.  The bark is streaked sooty-brown and looks very dark from a distance, like Corsican pine.

Black walnut with green fruit

Just before we reached Richmond Lock there was a solitary plant of Perennial Cornflower Centaurea montana, an increasing garden escape.

Perennial cornflower

Crossing the bridge at the lock, on the other side we immediately came across our first Galinsoga, both species at once, not only lots of Shaggy-soldier G. quadriradiata, with its long white hairs, but also one plant of Gallant-soldier G. parviflora, sometimes referred to as "Kew weed".  Being close to its relative, the smaller flowers and the shorter, less dense stem-hairs were very apparent.  It was ironic that we had to cross the river out of Kew before we saw it.

Gallant-soldier

Shaggy-soldier

Although there is no tow-path this side of the river, we could walk beside it almost as far as Syon House.  Quite a lot of the plants were different on this side of the Thames, including Mind-your-own-business Soleirolia soleirolii, Annual Wall-rocket Diplotaxis muralis, Mexican Fleabane Erigeron karvinskianus, Annual Mercury Mercurialis annua, the miniature "palm-trees" of Common Liverwort Marchantia polymorpha and, draping the hedges, Hop Humulus lupulus, with leaf-mines of the fly Agromyza flaviceps and the moth, restricted to SE England, Cosmopterix zieglerella.

Hop

It was here that we saw one of the specialities of the day, on the stone embankment descending to the river, a plant of Thames Yellow-cress, the hybrid Rorippa x erythrocaulis between Marsh and Great Yellow-cresses, which has small petals longer than the sepals, longish lobed leaves with clasping auricles, and fruits on widely spread-out stalks.

Thames Yellow-cress

          Birds on the Thames mud-banks were mostly Cormorant, Black-headed and Great Black-backed Gulls, and Canada Goose.

          At Syon Park we had to divert from the river to pass by the House, whose gardens were unfortunately closed today for a massive Indian wedding, so we could not check out the old black mulberries planted there.  After this the path sometimes follows the river and at other times we had to walk through back streets and along busy main roads.  Other wasteland plants seen occasionally in this stretch were Lucerne Medicago sativa ssp sativa, Tansy Tanacetum vulgare, Sea Beet Beta vulgaris ssp maritima (still within the tidal reach?), Common Poppy Papaver rhoeas, Goat's-rue Galega officinalis, and Autumn Stonecrop Sedum 'Herbstfreude'.

A street hedge had Hybrid Hazel Corylus avellana x maxima.

          When we reached Kew Bridge Station we crossed the bridge back to the Kew Gardens side of the river again.  The road goes straight past Kew Church, our last destination for the day, for we had one more speciality to see.  The churchyard is not too tidily manicured, leaving plenty of rough grass and a chance for wild plants to survive.  Here we saw Meadow Saffron again, Bear's-breech Acanthus mollis, Peach-leaved Bellflower Campanula persicifolia, and, for the first time, Perennial Rocket Sisymbrium strictissimum with unlobed leaves, hairy underneath, a tall striking plant.  Unfortunately it had mostly flowered long ago and all but one plant were very dry and brown, but the one younger specimen still had green pods and was possible to photograph in front of a tombstone.

Perennial rocket in seed, Kew Churchyard

A short walk brought us back near Kew Gardens tube-station with time for a coffee before enjoying a meal at the Glasshouse Restaurant and reflecting on a day that was not perhaps botanically great but still had plenty of interest and two rare plants in Thames Yellow-cress and Perennial Rocket.