project reflections #28

Upperthorpe Botanicus

Poor flowers in the flower beds of manicured gardens.

They look like they’re afraid of the police …

‘Alberto Caeiro’  from The Keeper of Sheep XXXIII

Feeling conscious of the absence of an introduction, I thought that it might be worthwhile to draft a short conclusion to the project reflections that I have written about the botany of the Upperthorpe, Netherthorpe, Shalesmoor, Neepsend and Wardsend edgelands (project reflections 1, 3, 4, 5, 14, 19, 20, 22, 24, 26 and 27 respectively).   

The aim, in principle, was to create a tentative psycho-botany of the various weeds and invasive plants that thrive on “disturbed ground” around the edges of habitation; to not only describe these ‘flowers that grow in the wrong places’ in botanical terms but to examine – at least in brief – their cultural significance.

Also, last weekend, whilst in conversation with a botanist friend, I was reminded of the fragile precariousness of this urban weed-ecology. Essentially most of these transitional or pioneering plants (poppies, buddleja, Rosebay willowherb etc.) will propagate only in areas of vegetation clearance; in the course of natural habitat development they will soon be deprived of light by forest canopies and, given time, will simply cease to exist. It is a transitory, human-determined and human-dependent flora that has been created in these areas.

In terms of the way that we have become accustomed to contemplating nature, I’m therefore left with somewhat conflicted feelings – where’s the (cleansing) spiritual connection? This is – it would seem – a somewhat muddied, muddled, mitigated nature; perhaps a somewhat less than fully ‘natural’ nature – in comparison to what we might hope to see in a timeless, ‘pristine’ ecology – perhaps in Alaska, for example …

In terms of structuring the texts, I quite enjoyed the caprice of writing the introductory (in bold) paragraphs in the ‘voice’ of an nineteenth century naturalist – a voice that I hoped would contrast with the ‘thick description’  or fact-heavy content of the remainder (culled heavily from Wikipedia but also informed by other texts including The Unofficial Countryside by Richard Mabey – and by a few personal experiences).

I also enjoyed the way that, at times, the language of botanical description formed a dense, impenetrable ‘thicket’ – growing from Greek and Latin roots. This was particularly evident when the botanical description of the complex structure of the common dandelion (Taraxacum officinale – project reflection 22) lead to a baroque profusion of technical terms: bracts (modified or specialized leaves, especially associated with reproductive structures such as flowers, inflorescence axes, or cone scales – from the Latin bractea, thin metal plate, gold leaf variant of brattea … of obscure origin); glabrous (having no hairs or protrusions – from Latin glaber – bald): involucres (a series of bracts beneath or around a flower cluster – French from Latin involocrum – wrapper, envelope); pappi (a modified calyx composed of scales, bristles, or featherlike hairs, in plants of the composite family, such as the dandelion and the thistle – Latin, old man, down on certain seeds, from Greek papposcalyx (the sepals of a flower collectively, forming the outer floral envelope that protects the developing flower bud – from Latin, from Greek – kalux shell, from kaluptein to cover, hide …

The reason for choosing Rosebay willowherb, bindweed, Japanese knotweed (donkey rhubarb) and dandelions was simple – they all feature on the weed control section of Sheffield City Council’s website. Poppies, bracken and briar, sycamore and buddleja were all chosen because they also fall within the categories of pioneering or invasive plants – and they all, on investigation, yielded surprising amounts of cultural – psycho-botanical – reference.

Paul Evans, 2012

project reflections #27

Moss 

Quiet, of course, it adheres to

The cracks of waste-pipes, velvets,

Velours them; an enriching

Unnatural ruff swathing the urban ‘manifestation’:

The urban nature is basemented, semi-dark:

It musts, it is alone. 

John Silkin,  Penguin Modern Poets 7

In the places that have most recently been abandoned to returning nature – such as disused car parks and the various hard standings from newly failed enterprise – we have found the first pioneering clumps of dark green moss. Somehow, these most ancient of botanical life-forms have found the most fragile of germinative footholds for their diminutive spores – often within the shallowest cracks created by fluctuations of heat or by settling of the ground.

It is thus the brave mosses that are the first to re-vivify the sterility of such terrain.

Favouring the dank (and low levels of light) these pioneering plants – known as bryophytes – began a very similar enterprise some 65,000,000 years ago; leaving the ancient seas to break ground across the barren land … and it was the dead, damp, mosses that made the first soils for the vascular plants that subsequently spread their living carpets across the earth.   

Mosses are small, soft plants that are typically 1–10 cm (0.4–4 in) tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems. At certain times mosses produce spore capsules which may appear as beak-like capsules borne aloft on thin stalks.

Botanically, mosses are bryophytes, or non-vascular plants. They differ from ‘higher’ plants by not having internal water-bearing vessels or veins, and no flowers and therefore no fruits, cones or seeds. They are small (a few centimeters tall) and herbaceous (nonwoody) and absorb water and nutrients through their leaves. Mosses have stems which may be simple or branched and upright or lax, simple leaves that often have midribs, roots (rhizoids) that anchor them to their substrate, and spore-bearing capsules on long stems. They harvest sunlight to create food through photosynthesis. Mosses do not absorb water or nutrients from their substrate through their roots, so while mosses often grow on trees, they are never parasitic on the tree.

They can be distinguished from the similar liverworts by their multi-cellular rhizoids. Also, in most mosses, the spore-bearing capsule enlarges and matures after its stalk elongates, while in liverworts the capsule enlarges and matures before its stalk elongates. Other differences are not universal for all mosses and all liverworts, but the presence of a clearly differentiated stem with simple-shaped, ribbed leaves – without deeply lobed or segmented leaves and not arranged in three ranks – all point to the plant being a moss.

There are approximately 12,000 species of moss classified in the Bryophyta.

Moss is often considered a weed in grass lawns, but is deliberately encouraged to grow under aesthetic principles exemplified by Japanese gardening. Moss is thought to add a sense of calm, age, and stillness to a garden scene.

A passing fad for moss-collecting in the late 19th century led to the establishment of mosseries in many British and American gardens. The mossery was typically constructed out of slatted wood, with a flat roof, open to the north side (maintaining shade). Samples of moss were installed in the cracks between wood slats. The whole mossery would then be regularly moistened to maintain growth.

project reflections #26

Burn Weed

It is my hope that it has now become apparent to the reader how many of the pioneering plants that I have thus far described employ – by means of adaptation – various ingenious biological defenses against the animals that might eat them.

These defenses constitute the great armoury of spines, thorns, prickles, bristles – and bitter, unsavory compounds and poisonous concoctions – that botanical nature has designed and brewed up to deter animal interest, investigation, and ingestion.In terms of our human experience of these arms and fortifications, there can surely be no more commonly suffered strategy than the sting of the common nettle – Urtica dioica. Every child – and every parent – must surely be conscious of that shockingly unpleasant ‘first contact’ with this painful weed; of the alarming white bumps and reddened skin that we associate with ‘nettle rash’.

Stinging nettle or common nettle, Urtica dioica, is a herbaceous perennial flowering plant, native to Europe, Asia, northern Africa and North America – it is the best-known member of the genus Urtica. The plant has many hollow stinging hairs called trichomes on its leaves and stems, which act like hypodermic needles; injecting histamine and other chemicals that produce a stinging sensation when contacted by humans and other animals. The plant has a long history of use as a medicine and as a food source.

Stinging nettle is a dioecious herbaceous perennial, 1 to 2 m (3 to 7 ft) tall in the summer and dying down to the ground in winter. It has widely spreading rhizomes and stolons, which are bright yellow, as are the roots. The soft green leaves are 3 to 15 cm (1 to 6 in) long and are borne oppositely on an erect wiry green stem. The leaves have a strongly serrated margin, a cordate base, and an acuminate tip with a terminal leaf tooth longer than adjacent laterals. It bears numerous small, greenish or brownish flowers in dense axillary inflorescences.

The leaves and stems are very hairy with non-stinging hairs and they also bear many stinging hairs (trichomes), whose tips come off when touched, transforming the hair into a needle that will inject several chemicals: acetylcholine, histamine, 5-HT (serotonin), moroidin, leukotrienes, and – possibly – formic acid. This mixture of chemical compounds causes a painful sting or paresthesia from which the species derives its common name, as well as the colloquial names: burn nettle, burn weed, burn hazel.

Urtication, or flogging with nettles, is the process of deliberately applying stinging nettles to the skin in order to provoke inflammation. An agent thus used is known as a rubefacient (something that causes redness). This is done as a folk remedy for rheumatism, providing temporary relief from (or at least a novel replacement for) pain in the joints.

As Old English stiðe, nettle is one of the nine plants invoked in the pagan Anglo-Saxon Nine Herbs Charm, recorded in the 10th century. Nettle was believed to be a galactagogue, a substance that promotes lactation.

Because it contains 3,4-divanillyltetrahydrofuran, certain extracts of the nettle are used by bodybuilders in an effort to increase free testosterone.

An annual Stinging Nettle Eating Championship draws thousands of people to Dorset, where competitors attempt to eat as much of the raw plant as possible. Competitors are given 60 cm (20 in) stalks of the plant, from which they strip the leaves and eat them. Whoever strips and eats the most stinging nettle leaves in a fixed time is the winner. The competition dates back to 1986, when two neighbouring farmers attempted to settle a dispute about which had the worst infestation of nettles.

In Europe stinging nettles have a strong association with human habitation and buildings. The presence of nettles may indicate that a building has been long abandoned. Human and animal waste may be responsible for elevated levels of phosphate and nitrogen in the soil, providing an ideal environment for stinging nettles.

Paul Evans, February 2012

project reflections #24

Senecio

It is night and snow has fallen – blanketing all signs of vegetation in a thick meringue covering that, in a way that is somehow disturbing, reflects the lurid acid yellow of the street lights. Sticks of black shrubs and the naked boughs of plane trees stand out in sharp, angular contrast – Upperthorpe is transformed. All is quiet.

Trudging wearily through the winding ankle-deep paths that criss-cross the disused factory lots, wastelands and brownfield sites, it is hard to imagine that hot day when we followed these self-same lines of passage, punctuated with the sunny yellow flower heads of various nodding ragworts and groundsels … and, in the autumn, the downy, grey, globed heads of seed that earns the genus the name of Senecio – or old man.

The ragworts are asters – and, like the dandelion, they would seem to offer a particular challenge to taxonomists. For one species alone, Oxford ragwort (Senecio squalidus), there are over 21 scientific synonyms and, in addition, the misapplied name of Senecio nebrodensis. A North American species Packera aurea (formerly Senecio aureus), commonly known as Golden Ragwort, has two synonyms and is also commonly known as Life Root, Squaw Weed, Golden Sececio, ragwort, uncum root, waw weed, uncum, false valerian, cough weed, female regulator, cocash weed, ragweed, staggerwort, and St. James wort.

There is, I believe, a much contested myth concerning the number of words for snow in the Eskimo-Aleut languages. Perhaps this discredited idea could be given up, instead, to the English (and Latin) for ragworts?

Senecio is a genus of the daisy family (Asteraceae) that includes ragworts and groundsels. The flower heads are normally rayed, completely yellow, and the heads are borne in branched clusters. Senecio is one of the largest genera of flowering plants and despite the separation of many species into other genera it still contains over 1250 species of varied form, including leaf, stem and tuber succulents, annuals, perennials, aquatics, climbers, shrubs and small trees. Some species produce natural biocides to deter or even kill animals that would eat them.

Oxford ragwort (Senecio squalidus) was first introduced into Britain via Francisco Cupani and William Sherard in the years of their visit 1700, 1701 and 1702 from Sicily – where it lives as a native on volcanic ash – to the Duchess of Beaufort’s garden at Badminton. Later a transfer of the genetic material to the Oxford Botanic Garden by the “Horti Praefectus” (the title still given to the head gardener at the Oxford Botanic Garden), Jacob Bobart the Younger, before his death in 1719. This is also the same year that Bobart retired as Horti Praefectus and perhaps a good indication of when this species of ragwort and other invasive species might have “escaped” and started to make their home in the greater British Isles. The Sicilian ragwort escaped into the wild and grew in the stonework of the colleges (there is a specific mention in the historical literature of the Bodleian library) and many of the stone walls around the city of Oxford. This gave the plant its common name, “Oxford Ragwort”.

Carolus Linnaeus first described Senecio squalidus in 1753, although there is a dispute as to whether the material came from the Botanic Garden or from walls in the city; the taxonomy for this species is further complicated by the existence of species with a similar morphology in continental Europe. James Edward Smith officially identified the escaped Oxford ragwort with its formal name Senecio squalidus in 1800.

During the Industrial Revolution, Oxford became connected to the railway system and the plant gained a new habitat in the railway lines clinker beds, gradually spreading via the railway to other parts of the country. The process was accelerated by the movement of the trains and the limestone ballast that provides a well-drained medium – an adequate replica of the lava soils of its native home in Sicily.

The vortex of air following the express train carries the fruits in its wake. I have seen them enter a railway-carriage window near Oxford and remain suspended in the air in the compartment until they found an exit at Tilehurst.

George Druce 1927

During the 20th century it continued to spread along railway lines and found a liking for waste places and bombed sites after World War II – which have a lot in common with the volcanic regions of Senecio squalidus’  home terrain.

Paul Evans, February 2012

project reflections #22

Taraxacum officinale

Escaping in memory from the season’s harsh, chill winds, I cast my mind back to the dandelion days of last spring, summer and early autumn. From March until October the vivid, cadmium yellow flowers of Taraxacum officinale, or common dandelion – and their superceding, globular silver seed-heads – are found to be distributed widely and in abundance across the gently dipping shoulders of the Don river valley. 

We have thus observed the dandelion – that most cosmopolitan of weeds – on many patches of wasteland and also, in naughty proliferation, across the cultivated lawns and pastures of Netherthorpe, Upperthorpe, Shalesmoor, Neepsend and Wardsend.

The dandelion is such a common plant that it is all to easy to become blind to its two extraordinarily complex stages of fruit and flower … but it is equal in its mystery to any other of the botanical organisms that we have encountered on our journeys around these parts. Not least, it would appear to confound the efforts of taxonomists to define its species with any precision – which is perhaps no surprise when one gives due consideration to this humble plant’s very singular ability to propagate in such numbers and to spread it’s progeny so widely and with such abandon through the action of the wind. 

Taraxacum officinale, the common dandelion (often simply called “dandelion”), is a herbaceous perennial plant of the family Asteraceae (Compositae). It can be found growing in temperate regions of the world, in lawns, on roadsides, on disturbed banks, on the shores of water ways, and other areas with moist soils. Taraxacum officinale is considered a weed species, especially in lawns and along roadsides; but it is sometimes used as a medicinal and in food preparation. As a nearly cosmopolitan weed, the common dandelion is best known for its bright yellow flower heads that turn into round balls of silver tufted fruits that blow away on the wind.

The dandelion grows from generally unbranched taproots and produces one to more than ten stems that are typically 5 to 40 cm tall but sometimes up to 70 cm tall. The stems can be tinted purplish, are upright or lax, and produce flower heads that are held as tall or taller than the foliage. The foliage is upright growing or horizontally orientated, with leaves that are unwinged or having narrowly winged petioles. The stems can be glabrous or are sparsely covered with short hairs. The 5–45 cm long and 1–10 cm wide leaves are oblanceolate, oblong, or obovate in shape with the bases gradually narrowing to the petiole  The leaf margins are typically shallowly lobed to deeply lobed and often lacerate or toothed with sharp or dull teeth and the leaves are all basal; each flowering stem lacks bracts and has one single flower head.

The yellow flower heads lack receptacle bracts and all the flowers, which are called florets, are ligulate and bisexual. The calyculi (the cup like bracts that hold the florets) are composed of 12 to 18 segments: each segment is reflexed and sometimes glaucous. The lanceolate shaped bractlets are in 2 series with the apices acuminate in shape. The 14 to 25 mm wide involucres are green to dark green or brownish green with the tips dark gray or purplish. The florets number 40 to over 100 per head, having corollas that are yellow or orange-yellow in color. The fruits, which are called cypselae, range in color from olive-green or olive-brown to straw-colored to grayish, they are oblanceoloid in shape and 2 to 3 mm long with slender beaks. The fruits have 4 to 12 ribs that have sharp edges. The fruits are mostly produced by apomixis (a form of asexual reproduction through the seeds). It blooms from March until October.

The silky pappi, which form the parachutes, are white to silver-white in color and around 6 mm wide. Dandelion plants have milky sap that has been used as a mosquito repellent; the milk has also been used to treat warts, as a folk remedy.

Taraxacum officinale is a common colonizer after fires, both from wind blown seeds and seed germination from the seed bank. The seeds remain viable in the seed bank for many years, with one study showing germination after nine years. This species is a somewhat prolific seed producer, with 54 to 172 seeds produced per head, and a single plant can produce more than 5,000 seeds a year. It is estimated that more than 97,000,000 seeds/hectare could be produced yearly by a dense stand of dandelions. When released, the seeds can be spread by the wind up to several hundred meters from their source, the seeds are also a common contaminate in crop and forage seeds.

The dandelion has historically had many English common names including: blowball, lion’s-tooth, cankerwort, milk-witch, yellow-gowan, Irish daisy, monks-head, priest’s-crown and puff-ball; other common names include: faceclock, pee-a-bed, wet-a-bed, canker-wort, and swine’s snout

Carl Linnaeus named the species Leondonton Taraxacum in 1753. The genus name Taraxacum, might be from the Arabic word “Tharakhchakon“,or from the Greek “Tarraxos“. The common name “dandelion,” comes from the French phrase “dent de lion” which means “lion’s tooth”, in reference to the jagged shaped foliage. The taxonomy of the genus Taraxacum is complicated by apomictic and polyploid lineages, and the taxonomy and nomenclatural situation of Taraxacum officinale is not yet fully resolved. This situation has been further complicated in the past by the recognition of numerous species, subspecies and microspecies. E.g. Rothmaler’s flora of Germany recognizes roughly 70 microspecies.

While the dandelion is considered a weed by most gardeners and lawn owners, the plant has several culinary uses. The specific name officinalis refers to its value as a medicinal herb, and is derived from the word opificina, later officina, meaning a workshop or pharmacy. Dandelion flowers can be used to make dandelion wine; and it has also been used in a saison ale called Pissenlit (literally “wet the bed” in French) which is made in Belgium. The greens are used in salads, the roots have been used to make a coffee-like drink and the plant was used by Native Americans as a food and medicine. Ground roasted dandelion root can be used as a coffee substitute. In Silesia, and other parts of Poland, dandelion flowers are used to make a honey substitute, to which lemon is added (so-called May-honey). This “honey” is believed to have a medicinal value, in particular against liver problems.

Dandelion root is a registered drug in Canada, sold principally as a diuretic. A leaf decoction can be drunk to “purify the blood”, for the treatment of anemia, jaundice, and also for nervousness. A hepatoprotective effect of chemicals extracted from dandelion root has been reported. Drunk before meals, dandelion root coffee is claimed to stimulate digestive functions and function as a liver tonic.


Paul Evans, 22 January 2012

project reflections #20

Sycamore

In order to escape the violent winds that blew in these parts throughout early January, I took to rambling through the scattered woodlands along the banks of the river Don. Here I found many large sycamore maples or Acer pseudoplatanus  – a magnificent tree that will sometimes grow to a height of over a hundred feet.

I have observed that, in wet ground at the base of these sycamores, the rocking movement of the tree in high winds – transmitted from the upper branches down through the solid trunk – results in oscillatory movements within pools formed from groundwater. This fluid moves up and down with the back and forth movement, resulting in the water rising up and withdrawing – almost like breath – and often expelling the liquified soil to create cavities amongst the roots. These cavities are, I am led to understand, known as oscillants …

Acer pseudoplatanus, the sycamore maple, is a species of maple native to central Europe and southwestern Asia, from France it is naturally distributed eastwards towards the Ukraine, and south to northern Spain, northern Turkey, and the Caucasus. It is not related to other trees called sycamore or plane tree in the Platanus genus. Its apparent similarity to the species of that genus led to its being named pseudoplatanus, using the prefix pseudo- (from the Ancient Greek for “false”). Other common names for the tree include false plane-tree, great maple, Scottish maple, mock-plane, sycamore or Celtic maple.

It is a large deciduous tree that reaches 20–35 m tall at maturity, with a broad, domed crown. On young trees, the bark is smooth and grey but becomes rougher with age and breaks up in scales, exposing the pale-brown-to-pinkish inner bark. The leaves are opposite, large, 10–25 cm long and broad with a 5–15 cm petiole, with a leathery texture, palmately veined with thick veins protruding on the underside surface, with five lobes with toothed edges, and dark green in colour with a whitish underside. The leaves are often marked with black spots or patches which are caused by the fungus Rhytisma acerinum. The monoecious yellow-green flowers are produced in spring on 10–20 cm pendulous racemes, with 20–50 flowers on each stalk. The 5–10 mm diameter seeds are paired in samaras, each seed with a 20–40 mm long wing to catch the wind and rotate when they fall; this helps them to spread further from the parent tree. The seeds are mature in autumn about 6 months after pollination.

The name “sycamore” originally belongs to the fig species Ficus sycomorus, which is native to southwest Asia (this is the sycamore or sycomore referred to in the Bible). The name was later applied to this species by reason of the superficial similarity in leaf shape.

The sycamore is cultivated and widely naturalised north of its native range in northern Europe, and it now occurs throughout the British Isles, having been introduced in the 17th century. It is considered to be an environmental weed in environmentally sensitive locations.

The wood is a medium weight hardwood, weighing 630 kg per cubic metre. It is traditionally used in making the backs, necks and scrolls of violins. The flowers produce abundant nectar, which makes a fragrant, delicately flavoured and pale-coloured honey.

Paul Evans, 8 January 2012