Guest blog by: Sophie Mogg
I’m taking a break from my travels to celebrate world soil day. World soil day celebrates the importance of soil in our natural environment and contributes enormously to human well-being through providing a place to grow crops and supporting all walks of life.
In many parts of the world soil is now contaminated with heavy metals and radioactive elements as a by product of mining and various other human activities. This renders the soil unusable and unsuitable for feeding livestock, growing crops and restoring natural habitats. However there are many plants, known as hyperaccumulators, that are able to absorb these heavy metals through their roots, often concentrating them in their leaves. This process is known as phytoremediation. These metals can be retrieved from the plants by burning them, a process known as phytomining. By using natural hyperaccumulators we can reclaim those areas affected by mining and hopefully restore some natural habitats in the process.
Here are some of those wonderful plants from our collection, enjoy!
Guest blog by: Laura Cooper
Whilst volunteering at the herbarium I came across several small boxes containing bewitchingly bright red seeds and an equally garish TOXIC sign. They were labelled Abrus precatorius seeds, and that one of their common names is the rosary pea suggests that I am not the first to be taken in by their beauty. The seeds of Abrus precatorius have the eye-catching red of hawthorn berries capped with a black spot at the hilum, but glossy and sturdy enough to be drilled to make beads for jewellery.
The contrast between the beauty of the seeds and their toxicity inspired us to begin a blog series on toxic plants called The Poison Chronicles. We want to look at how they can kill, but also why they have evolved this ability and if the plant has any other products that are medicinally useful.
Abrus precatorius is a vine in the Legume family native to the Old World Tropics, but was introduced to the Neotropics for it’s ornamental value, but is now an invasive species. It proliferates after a forest fire so can out-compete slower growing plants, it’s suckering ability makes it difficult to remove.
But these seeds are more than just beautiful. They have earned their TOXIC label as they contain the toxin abrin, which has a very low fatal dose, reported in the literature as around 0.1 – 1μg/kg, making it one of the most toxic known plant products. Abrin acts by inhibiting protein synthesis, so can affect all cells in the body. A few hours after a person has ingested a lethal dose of abrin, they may experience severe vomiting, gastrointestinal bleeding, dehydration, multi-organ damage and death often within 36-72 hours. The incredible toxicity of abrin was occasionally used to secretly kill people in 19th century Bengal. The seeds were ground into a paste, shaping into a point known as a sui and left to harden in the sun. This was then mounted on a handle and stuck through the person’s skin by a surreptitious slap to the cheek.
Despite this toxic plant being widespread, there have been very few cases of abrin poisoning. The thick indigestible coat of mature seeds meaning that if seeds are swallowed whole, they are unlikely to release much abrin and symptoms are mild. Chewing the seed releases the toxin, and it has been reported that a single well chewed seed could kill. However, a case of a patient attempting suicide through ingesting 10 crushed A. precatorius seeds survived after swallowing activated charcoal. Except when used or taken deliberately, it is surprisingly difficult for humans to be poisoned by A. precatorius, so for most this plant poses more of a threat to your garden as an invasive than your health.
An obvious question is why these seeds contain such a deadly toxin. I have been unable to find any research on this. But it may be that the thick seed coat means the toxin isn’t a defence against herbivores ingesting the seeds at all. As it has been reported that the seed is dispersed by birds who would not chew the seed and would instead disperse them in faeces, it is possible it is a defence against mammals chewing the seeds.
A. precatorius has not always been seen as a deadly beauty, and has been used a traditional medicine. Extracts of the seeds have been used in the Pothohar region of Pakistan as a purgative and an aphrodisiac and in rural Bangladesh to treat erectile dysfunction. The symptoms of poisoning by abrin suggests very low doses could work as a purgative, there is a high risk of administering a lethally high dose.
A. precatorius‘ entire biochemical system makes it toxic, so single chemical plucked out of this network can have very different properties from the plant as a whole. In contrast its traditional uses, experiments have been done which show that abrin injected into laboratory mice damages the DNA and reduces production of sperm cells, though the long time period needed for DNA repair to occur means it is unlikely to be used in commercial birth control.
Abrus precatorius demonstrates the multi-faceted nature of plants: at once a beauty and a (potential) killer; a toxin and used as a medicine.
We hope you have enjoyed our first installment of The Poison Chronicles. You can find more information following the link below
What wondrously poisonous plant would like to find out about next? Leave your comments below.
By Berglind Kristjansdottir
The Herbarium has a lot of specimens collected by Joseph Dalton Hooker (f. 1817, d. 1911). Most of them are from his expedition to India were he collected plants in and around the Himalayas.
Sir Joseph Dalton Hooker and his Exploration of Nepal and Sikkim
Sir Joseph Dalton Hooker was born in Halesworth, Suffolk in 1817. He spent his childhood in Glasgow were he helped his father with his herbarium which nurtured his keen interest in plants. Later in his life he would become one of the key scientists of his age and the most important botanist of the nineteenth century.
Hooker was only 15 years old when he entered the Glasgow University to study medicine. There he met Charles Darwin, who became one of his closest friends, and Captain James Clark Ross. Ross was about to lead a British Association expedition to the Antarctic and Hooker was determined to join. His father helped his 22 year old son to get the position of assistant ship’s doctor and botanist. On 28 September 1839 Hooker sailed out of the Medway and didn’t return until four years later. During the trip he was able to botanize on three continents as the ship visited Madeira, the Cape of Good Hope, Tasmania, New Zealand, Australia, the Falkland Island and the Southern tip of South America. His discoveries led to the foundation for his authority on the geographical distribution of plants, which later would prove vital to Darwin and his theory of evolution.
When Hooker came back to England in 1841 he was determined to make a study of tropical botany to compare to the Antarctic and on 11 November 1847 he left for a two year plant hunting trip to Sikkim on behalf of Kew. He arrived at Darjeeling on 16 April 1848. Hooker wanted to travel to Sikkim’s high mountain passes but to do that he needed permission from the Rajah. It took Hooker almost a year to get Sikkimese authorities to approve his application and on 27 October 1848 he was finally able to set out for Sikkim with his party of fifty-five men. The trip to the passes wasn’t easy. There were no proper roads to follow and they had to travel by foot. As winter approached the conditions deteriorated. The expedition got more and more dangerous and Hooker and his party had various complications on the way like imprisonment by the Dewan of Sikkim and lack of supplies and food.
The Himalayan expedition took Hooker three years and made him the first European to collect plants in the Himalaya. He collected a lot of important and special plants while he was there but the discovery and introduction into English gardens of the numerous and gorgeous Sikkim Rhododendron was certainly one of his greatest achievements. Out of forty-three species he collected thirty who were considered new to botanists, and most of the others were yet unknown to them.
Rhododendrons of the Sikkim-Himalaya
In May 1848 Hooker first experienced the excitement of discovering a new rhododendron. He found the ivory-white-flowered Rhododendron grande (R. argenteum) at the top of Mt Sinchul south east of Darjeeling. In his book Himalayan Journals Hooker described this plant as a:
“…tree forty feet high, with magnificent leaves twelve to fifteen inches long, deep green, wrinkled above and silvery below, while the flowers are as large as those of R. Dalhousie and grow more in a cluster. I know nothing of the kind that exceeds in beauty the flowering branch of R. argenteum, with its wide spreading foliage and glorious mass of flowers” (Hooker, 2016).
Later in May when he was in Mt Tonglo he found Rhododendron falconeri which has reddish bark and beautiful bell-shaped yellow flowers. Hooker described it as:
“…in point of foliage the most superb of all the Himalayan species, with trunks thirty feet high, and branches bearing at their ends only leaves eighteen inches long: these are deep green above, and covered beneath with a rich brown down” (Hooker, 2016).
In the Yangma valley at the Yangma Pass (16,168ft) he found the graceful Rhododendron campylocarpum. In the book Rhododendrons of the Sikkim-Himalaya (1849-1851) Hooker described the plant as:
“A small bush, averaging six feet in height, rounded in form, of a bright cheerful green hue, and which, when loaded with its inflorescence of surpassing delicacy and grace, claims precedence over its more gaudy congeners, and has always been regarded by me as the most charming of the Sikkim Rhododendrons” (Hooker, 1849).
Rhododendron maddeni is one of the “original” rhododendrons first introduced from the Himalaya by Hooker in the mid-1800s. It was named for Lt.-Col. E. Madden, a member of the Bengal Civil Service. In Rhododendrons of the Sikkim-Himalaya Hooker wrote:
“I do myself the pleasure to name this truly superb plant in compliment to Major Madden of the Bengal Civil Service, a good and accomplished botanist, to whose learned memoirs on the plants of the temperate and tropical zones of North-west Himalaya, the reader may be referred for an excellent account of the vegetation of those regions. The same gentleman’s paper on the Coniferae of the north of India may be quoted as a model of its kind” (Hooker, 1849).
Rhododendron arboreum is an evergreen shrub or small tree with a showy display of bright red flowers. It is found in Bhutan, China, India, Myanmar, Nepal, Sri Lanka and Thailand. Rhododendron arboreum is the national flower of Nepal and in India it is the state tree of Uttarakhand and state flower of Himachal Pradesh and Nagaland. R. arboreum was first of the Indian Rhododendrons to be discovered. In Rhododendrons of the Sikkim-Himalaya it says:
“Towards the very close of the 18th century, namely in 1700, R. arboreum, the first of a new form and aspect of the genus, and peculiar to the lofty mountains of India Proper, was discovered by Captain Hardwicke, in the Sewalic chain of the Himalaya, while he was on a tour to Sireenagur. The species has since been found to have a very extended range” (Hooker, 1849).
Desmond, R. (1990). Sir Joseph Dalton Hooker Traveller and Plant Collector. Woodbridge, Suffolk: The Antique Collectors’ Club.
Hooker, J. D. (1849). Rhododendrons of the Sikkim-Himalaya. London: Reeve, Benham, and Reeve.
Hooker, J. D. (2016). Himalayan Journals (first published 1854). Oxon: Routledge.
Musgrave, T. Gardner, C & Musgrave, W. (1998). The Plant Hunters. London: Ward Lock.
Last week, Daniel Atherton and Leslie Hurst from the National Trust gave us an wonderful tour of the gardens of Biddulph Grange (see Campbell’s post on the Egyptian garden here). Unfortunately, little information is available about the gardens as they were being created by the horticulturally-enthusiastic owners James and Maria Bateman (between 1840 and 1861). With the Head Gardener’s logbooks missing, the restoration of the garden has relied on other sources such as letters between Bateman, botanists and plant hunters, books logging out-going plants from specialist nurseries and descriptions from garden visitors.
The Leo Grindon Cultivated plants collection is full of specimens from notable gardens as well as a host of newspaper cuttings, magazine prints, notes and letters. With such a wealth of information, progress has been slow in documenting this collection, and so it remains an exciting treasure-trove of little-explored gems. I wondered whether there would be any references to Bateman or Biddulph Grange in the collection ….but where to start?
James Bateman is famous for his beautifully illustrated volumes on orchids, and sure enough, it wasn’t long before I uncovered some articles which Leo Grindon thought interesting enough to add into his ‘general Orchid’ selection.
This article from the Gardener’s Chronicle (Saturday, November 25th, 1871) is a biography of Bateman and his importance in the 19th century horticultural world. This quote caught my eye:
“Some of the effects, from a landscape gardener’s point of view, were strikingly beautiful, many quaint and grotesque. Had these latter been carried out by a person of less natural taste than Mr Bateman, they would have degenerated into the cockney style. In Mr Bateman’s case there was the less risk of this as, in addition to his own good taste and feeling for the appropriate, he was aided by Mr. E. W. Cooke, the eminent painter, and we may write, plant lover.”
….but I’m still not certain how complimentary this is! Another clipping touches on Bateman’s position in the debate between emerging scientific ideas and the Christian view of the creation of the earth. The geology gallery at Biddulph is a remarkable melding of Bateman’s religion with 19th century scientific discovery in stones and fossils (follow PalaeoManchester for more on this story).
Then there are a few cuttings covering James Bateman’s lectures giving summaries of the information he shared. These cuttings are typical of Leo Grindon’s collection as he rarely recorded the source of his material, or the date of publication. Presumably he was so familiar with the style of the various magazines and papers which he subscribed to that he never saw the need to write these details down.
These cuttings show that Leo Grindon was definitely following the work of James Bateman, but what of the gardens of Biddulph? For the next installment I think we shall have to move into another famous section of the garden, the Himalayan Glen, and delve into the herbarium’s Rhododendron folders to look for more clues.
To be continued……
Exciting changes ahead for Manchester Museum….
Manchester Museum, part of The University of Manchester, has received initial support from the Heritage Lottery Fund (HLF) for its Courtyard Project. The project will transform the Museum with a major two-storey extension, a new main entrance, and much-improved visitor facilities inspired by a new ethos of a ‘museum for life.’
Manchester Museum – possible perspective render
Work will commence in May 2018 and the finished building will reopen in early 2020. Development funding of £406,400 has been awarded to help Manchester Museum progress its plans to apply for a full grant at a later date.
The Courtyard extension will create a major new Temporary Exhibitions Gallery, providing almost three times as much space as the Museum currently has for temporary and touring shows. The new facility will enable the Museum to become one of the North of England’s leading venues for producing and hosting international-quality exhibitions on human cultures…
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Yesterday saw a group of first-year undergraduates braving the baking Mediterranean sun for the first day trip of the Comparative and Adaptive Biology field course. The Bocquer Valley near the town of Pollenca is a great place to look for Mallorcan endemic ‘hedgehog’ plants Teucrium subspinosum and Astragalus balearicus. While the students investigated the distribution of these small spiny shrubs, the staff took the opportunity to do a little more plant hunting.
One beautiful plant we regularly see in flower is the Balearic cyclamen (Cyclamen balearicum). It has very marbled leaves and delicate white flowers and hides in the shade of the larger shrubs. We also find the leaves of the Mallorcan peony (Paeonia cambessedessii). We visit far too late to see it in flower, but we’ve never found fruit either, suggesting that these plants didn’t flower in February or March. Perhaps these are young plants, or perhaps this is an indication of the difficult environment in the valley. This peony is named for the French botanist Jacques Cambessedes (1799-1863) who studied the plants of the Balearic Islands in 1825 and published the account of his travels and his work on the flora in 1826 and 1827.
One plant we’ve not spotted on our previous visits is the Dead-horse arum (Helicodiceros muscivorus). Given that it was behind a tree, under a shrub and in the bottom of a drainage channel, it’s not too surprising that we’ve not found it before. This plant has striking arrow-shaped leaves (sagittate leaves) and a flower spike (spadix) enclosed in a sheath known as a spathe. This specimen had not yet opened, and the geometrically patterned spathe was still closed shut. I’m not sure that I was too disappointed as the plant attracts pollinating flies with heat and rotting carcass smells.
After a year of full closure while the Museum roof was rebuilt and about a further 5 years of disruption since the window replacement work began, we finally have the herbarium back up and running. So we thought it was high time to host a party to remind the rest of the Museum and the University’s plant scientists just how lovely our store room is.
We laid out examples of our current projects, some of our favourite objects and quirky things that we’ve come across while we’ve been sorting the place out. After everyone had explored the collection we all headed off to the staff room for some delicious botanically-themed cakes.
We should do this more often!