Dandelion: a useful weed?

Common dandelion (Taraxacum officinale). Image by Franz Eugen Köhler, Köhler's Medizinal-Pflanzen (public domain).

Common dandelion (Taraxacum officinale). Image by Franz Eugen Köhler, Köhler’s Medizinal-Pflanzen (public domain).

I have recently moved house and I now have a small garden to take care of. I’m pretty excited by this prospect and have been trying to decide what to try and grow in in it. However, my little garden is currently somewhat overgrown with weeds—most of which are dandelions.

The common dandelion (Taraxacum officinale) belongs to the Daisy family (Compositae/Asteraceae) of flowering plants alongside more popular garden plants such as sunflowers. It is native to Eurasia but has spread to many other parts of the world including North America. The name dandelion derives from the French ‘dent de lion’, which means ‘lion’s tooth’ and refers to the deeply toothed leaves (1).

A common cause of frustration to gardeners, the common dandelion has several features that enable it to be a vigorous weed in most types of soil. Each flower head produces around 2000 seeds in white tufted fruits that form a puffy ball on the plant (so-called “dandelion clocks”). The seeds are dispersed by the wind and can survive dormant in the soil for many years until the conditions are right for them to germinate. Also, the plants produce a taproot that can grow up to 10-15 ft deep into the soil (2). Whole plants can regrow from a small fragment of taproot, which means that it can be very difficult to remove them from your garden.

When I was a child growing up in London, there was a house near me where, rumour had it, a hermit lived by eating the dandelions growing in his back garden. This story is, admittedly, probably just the imaginings of local children, but it isn’t quite as far-fetched as you might think. Dandelions are indeed edible: the leaves can be served raw or cooked and the flowers are used to make drinks including wine or cordial. Even the root is edible, and in the UK it was commonly ground up and to make a coffee substitute during the Second World War (1).

The common dandelion has other useful qualities. It is a diuretic and a laxative and has been traditionally used in medicine as a tonic, for rheumatic problems, and to purify the blood (1). Also, dandelions produce a milky-coloured sap that contains latex (rubber). The demand for latex is fueling research efforts to harvest it from dandelions. These efforts are focussing on the Russian dandelion (Taraxacum kok-saghyz), which produces sap with higher latex content than the common dandelion (3, 4).

So, a plant that is considered to be an annoying weed by many can be considered useful to others. The plant scientist in me does admire dandelions, but that isn’t going to stop me from trying to remove most of them from my flowerbeds. Let battle commence.

Common dandelions in bloom in my garden (Norwich, UK)

Common dandelions in bloom in my garden (Norfolk, UK)

Quite by accident Plant Scientist appears to be having a weed-themed month. Stay-tuned for more posts about plants that often find themselves in the “wrong” places.

In other news, this is the 100th post on the blog. Hooray!


  1. Kew – Taraxacum officinale (dandelion) (retrieved 11/05/15)
  2. UC IPM – How to manage pests: Dandelions (retrieved 11/05/15)
  3. Science Daily – Rubber from Dandelions: Key components in formation of rubber identified. (retrieved 11/05/15)
  4. Science Daily – Making rubber from dandelion juice (retrieved 11/05/15)

Guest post. The private life of a common garden weed

By Guru V Radhakrishnan (@guru_vighnesh)

Gametophyte of Marchantia polymorpha subsp. ruderalis in Brandenberg, Germany. Splash cups are visible on some of the thalli.

Marchantia polymorpha subsp. ruderalis growing in Brandenberg, Germany. Splash cups are visible on some of the thalli. Image by Franz Mattuschka (CC BY-SA3.0) via Wikimedia Commons

The umbrella liverwort (Marchantia polymorpha) is a noxious weed. It grows in most gardens, paths and glasshouses, and is found in almost all parts of the world – from tropical to arctic climates. There are several subspecies of this plant that are found in damp habitats at varying altitudes. The plants themselves are of little economic importance, but in ancient times, liverworts were believed to be a cure for liver diseases. This ancient idea was part of the “doctrine of signatures” [1]. This doctrine suggested that plants resembling a certain body part could be used to treat ailments of that body part. Although an interesting idea, there is no scientific evidence to support this claim.

The genus name Marchantia comes from the name of a French botanist Nicholas Marchant. And the species name polymorpha is Greek for many forms (polymorph). This name comes from the ability of these plants to take up different sizes, shapes and shades of green depending on the conditions they are grown in.

These liverworts, along with hornworts and mosses, form a group of plants known as the bryophytes. Of all the groups of plants that are alive today, the bryophytes are suggested to be the most ancient. The earliest ancestor of the bryophytes is thought to be ancestral to all other land plants [2]. Because of the evolutionary position of the liverworts, scientists are using M. polymorpha to understand how early land plants evolved.

Like all other land plants, liverworts also have two alternating stages in their life cycle, known as the sporophyte and the gametophyte. In ferns, seed plants and other higher plants, the structure we would recognise as being “the plant” is the sporophyte, and the gametophyte stage is short-lived. For example, in seed plants the gametophytes are the egg and sperm cells within the flowers or cones on the sporophyte. However, in bryophytes the gametophyte stage as the dominant part of their life cycle. In M. polymorpha, the gametophyte structure is known as the thallus – which is the green, flat plant body (see photo). The small sporophyte forms within the female sexual structures of the gametophyte, which is an umbrella-shaped structure called the archegonial head (see figure below).

M.polymorpha is dioecious, which means that there are separate male and female plants. The male plants only produce male sexual structures, which are known as antheridial heads, and female plants produce only female structures. When water falls onto the male plant, sperm can be released from the antheridial head and swim through the water to reach the archegonial head on a nearby female plant. Here, the sperm cells can fertilize egg cells leading to the production of millions of spores on the archegonial head. These spores are minute and can be transported by wind. Once the spores settle on a suitable part of the ground, they germinate into individual gametophytes.

Life cycle of M. polymorpha. The gametophyte is the dominant stage with the sporophytes forming in the archegonial heads of female gameophytes. Image by Lady of Hats released into public domain.

Life cycle of liverworts. The gametophyte is the dominant stage with the sporophytes forming in the archegonial heads of female gameophytes. Image by Lady of Hats (public domain) via Wikimedia Commons.

In addition to sexual reproduction, there is also asexual reproduction in liverworts. Here, specific cells separate themselves from the plant and start forming vegetative buds called gemmae. These gemmae originate from single cells and undergo multiple cell divisions. They accumulate in a specialised structure called a splash cup (or a gemma cup; see figure). These cups contain about a hundred gemmae. When water splashes onto these cups, the gemmae are catapulted out of the splash cups and fall on to the ground. They then continue to grow and become new plants.

These vigorous and efficient methods of reproduction help these plants to quickly colonise a patch of land after a fire. This is also why it is so hard to get rid of these plants from our gardens!

About the author: Guru is a PhD student at the John Innes Centre, UK studying how plants evolved the ability to interact with microbes. Follow him on twitter (@guru_vighnesh).

The umbrella liverwort is the Organism of the Month.


  1. https://en.wikipedia.org/wiki/Doctrine_of_signatures
  2. https://en.wikipedia.org/wiki/Evolution_of_plants

Two years on: what science blogging has done for me

S ShailesThis week marks the second birthday of this blog, which I started while I was in the final year of study for a PhD. At the time I was considering my next steps after finishing my studies. I wasn’t entirely sure what direction to take so I started blogging to give me more practice at writing and more experience of communicating science to non-specialist audiences. In doing so, I realised that I enjoy science writing much more than I ever expected.

During a PhD it is very easy to become so focussed on the tiny details of your research project that it is difficult to see the bigger picture, especially when experiments aren’t going to plan, or while writing a difficult passage of your thesis. Blogging gave me an excuse to step back and think about other areas of science that interested me so that I could face the difficulties in my PhD with a fresher perspective. It also reminded me that—although I loved my research project—I also had much broader interests in science that I had been neglecting.

Just like any skill, the more you practice writing, the easier it gets. By the time I came to write my thesis I was much more confident in my ability to write and I was much more disciplined. Before I started blogging, my writing efforts were usually peppered with large periods of procrastination in between short periods of actual progress. Now, I find it much easier to sit down and get writing and if I find a particular section is tricky to write, I will skip it and come back to it later. I’m convinced this made writing my PhD thesis much less painful and, in the end, it was one of the best times of my PhD.

Blogging has given me new opportunities, introduced me to new people, and taken my career in a new direction I would never have anticipated. Two years ago, if you had suggested that I should consider a career in science writing I would have dismissed it as being “not for me”. But here I am, working for a scientific journal and spending all day editing and writing content aiming to explain scientific research to non-specialists.

My main motivation for blogging—to practice writing—still remains. Now that I write for a living, the main advantage of running my own blog is that I have the opportunity to write about whatever I like, whenever I like. However, in some ways, it is harder to maintain the blog now than when I worked in research. Gone are the days where I could write a post inbetween experimental work in the lab. Now, I have a job with more regular working hours and so I can only write in the evenings or at weekends. Although I can write on my train journey to work, the lack of internet access means I need to have already researched the idea beforehand. The way that blogging fits into my life has changed, but I still enjoy writing it just as much.

Mystery flowering plant in Soma, The Gambia

Madagascar periwinkle (Catharanthus roseus) in Soma, The Gambia. Thanks to Steven Dodsworth for identifying it for me.

Plant Scientist reaches a wider audience than I ever expected it to. For that I need to thank you for reading, sharing and commenting on the posts. I also want to thank my guest contributors for providing different perspectives and interesting stories that broaden the content of the blog. Keep reading for more stories about plants, microbes and experiences of life in science!

I am always happy to receive guest posts so if you are interested in writing something for Plant Scientist please get in touch.

Guest Post: Finding the success in failure

By Kirsty Jackson (@kjjscience)

Image by Neil Moralee via Flickr (CC BY-NC-ND 2.0)

Image by Neil Moralee via Flickr (CC BY-NC-ND 2.0)

If you are a high achiever, it can be assumed that you will be able to conquer everything put before you with ease. Achievements that would be mammoth for the average person are supposed to be run of the mill for you. When you have spent all of your life hitting every goal set for you, it becomes impossible for people to imagine that you will fail at anything. Some lucky few live their lives never encountering failure, but the majority of us we will come across something, that no matter how hard we try, we cannot succeed in. Most people experience failure when they are younger and as such learn how to rationalise that failure and how to learn from it. This poses a philosophical question – If you learn from a failure, is it really a failure?

I have spent all of my life getting the best grades and fulfilling every expectation held for me, so when I did not pass my PhD viva exam I entered a difficult period. There was still a belief in me, and from others, that I had what it took to gain the PhD and should work to get the qualification because I had already sacrificed so much in an effort to gain it. I ploughed on ahead, fighting against the anguish I felt at not passing first time and trying desperately to keep up with what people expected of me. I kept being told I was “clever”, I was “technically proficient” enough to do it and I shouldn’t “waste all the time” I had already given to study. But I still awoke every morning feeling like I had barely slept and with a dread about taking myself back into the lab.

I’ve always had a determined, almost mule like, spirit when I decide I want to do something, but even this seemed to have deserted me. I didn’t feel like myself at all. This descended into me spending my evenings in tears and overeating to comfort myself. But still I continued to battle against all of my emotions because I MUST NOT FAIL. This became almost like a mantra and it didn’t matter how ill I was making myself. I was getting increasingly anxious and wanted to spend less and less time in the company of others, which is completely against my character. This was affecting my work: no matter how hard I was trying, my tiredness was not helping me gain those precious results I needed in the lab. Experiments that were almost routine to me were not working and I could not figure out why – which only added to my despair.

I started to think about what I would do if I ran out of time and funding to complete the experiments that were required for me to complete the PhD. I had been offered a Masters of Philosophy (MPhil) after my viva exam, but it is unusual to spend four years studying for an MPhil in science in the UK, so it could be a sign to others that I hadn’t managed to get a PhD. I started to think about what I would say to potential future employers, how I would have to re-live my failure every time I had a job interview and the questions that might arise. Then I thought about my family and how proud they had been of me, coming from a working class, separated family in London, rising through comprehensive schooling to the almost unimaginable heights of a PhD student. I was going to be a Dr, and in me I held all of their hopes and dreams. These things made me feel physically sick. I was going to be failing my family, and to me that was worse than failing myself. I had even been told by my husband that I should think myself lucky to have even had the chance to get a PhD.

I was spiralling down mentally and physically and was losing my ability to cope with the situation. I would look in the mirror and not even recognise the woman looking back at me. One day, when sat in a pool of used tissues, I felt something break within me. I knew that if I was going to carry on down this route I might not make it out the other side in a functional state. I have never been one to thrive on adrenaline and even theme park rides turn me into a jabbering wreck. The levels of stress I was going through was starting to damage my health. I knew then that I needed to get out, but still felt it was an impossible task.

I managed to pluck up the courage to talk about how I was feeling with a close friend (who had graduated recently with a PhD) and a couple of close family members. It started to become clear to me that my health was more important than the title I was chasing. I reflected upon everything I learned during my time studying for the PhD and it was anything but a waste of time. I had learned how to handle myself in difficult situations and become more organised. I had tons of self-discipline and my presentation skills, task management, problem solving skills, communication skills and critique skills had all vastly improved. I now also had in-depth knowledge of science research and how science works as a career.

Now that I had established that a life in science research was not going to be for me, I spent more time thinking about what I actually wanted to do with my life. During my undergraduate and my postgraduate studies I had participated in a lot of science outreach, teaching children about a variety of science topics far outside my specialism. I had always known that I enjoyed these school visits far more than I enjoyed my time in the lab. Teaching had crossed my mind when I was finishing my undergraduate degree, but I felt too young and inexperienced to make a good teacher. There is also a great stigma attached to becoming a teacher in this country with phrases like “If you can’t do, teach” being a common jibe at the profession. After investigation, it was clear that having a MPhil instead of a PhD would not make a large difference to me getting a place on a teacher-training course. It would mean a slightly smaller training bursary, but it definitely wasn’t a deal breaking difference. It wasn’t an easy decision to come to, but after five months of wrestling with it and a lot of discussions, I decided that I was going to be better off calling it a day and accepting the MPhil.

That just left one last hurdle, my Dad. I knew he wasn’t going to take my decision well. He had always been the one pushing my brother and me to try and always win, and always get the highest and best of everything possible. He saw the PhD as learning the skills to be a scientist, in the same way an apprentice learns the skills of a trade. It took another massive struggle within myself to call him. The conversation was short and carried a mixed message, his words saying one thing and the tone of his voice saying another. None the less, it was over. I sat on my sofa feeling both sad at his response, but strangely freed of a great burden. I am no longer “perfect”. I can now concentrate on finding that happy, confident young woman who used to stand before me in the mirror. I can put my efforts into fulfilling all the things I need to do to become a teacher in a subject that I still find fascinating, and pour my passion into something that I feel is truly worthwhile.

About the author: Kirsty Jackson has recently completed a MPhil in Plant Science in Norwich, UK. She intends to pursue a career in teaching so she can use her scientific knowledge to inspire the next generation of scientists. Follow her on twitter (@kjjscience).

Treating heart disease with foxgloves

Common foxglove flowers. The scientific name Digitalis means "finger-like". Image by H. Zell (CC BY-SA 3.0) via Wikimedia Commons.

Common foxglove flowers. The scientific name Digitalis means “finger-like”. Image by H. Zell (CC BY-SA 3.0) via Wikimedia Commons.

The common foxglove (Digitalis purpurea) is a pretty flower native to Western Europe. It is commonly found in open spaces especially in recently cleared woodland and other places where the ground has been disturbed, but is also popular in gardens as an ornamental plant (1). Although the plant is poisonous to eat, it has been used in traditional medicines for centuries, but it wasn’t until the 18th century that its medicinal benefits were thoroughly examined by a British doctor called William Withering (2).

Dropsy (now known as oedema) is the build up of fluid in the body. In the 18th century the condition was often fatal as patients could “drown” in the fluid that built up in their lungs. Dropsy can be caused by heart failure because the decreased flow of blood around the body leads to the kidneys retaining more fluid. Continue reading

Sharing plant genes to fight crop disease

Rice suffering from bacterial rice blight caused by Xanthomonas oryzae pv. oryzae. Image by International Rice Research Institute (IRRI) via Flickr (CC BY-NC-SA 2.0)

Rice suffering from bacterial rice blight caused by Xanthomonas oryzae pv. oryzae. Image by International Rice Research Institute (IRRI) via Flickr (CC BY-NC-SA 2.0)

In plants, the first line of defence against microbes involves the recognition of molecules that are produced by a wide variety of microbes. For example, many plants can detect the protein EF-Tu — which is essential for DNA replication in bacteria — and a molecule called chitin, which is found in the cell walls of fungi. Detection of these molecules activates defence responses that are thought to be able to repel most microbes.

However, some microbes are able to avoid these defences and so plants need to be able to employ other defence strategies that are targeted at those particular microbes. These defences involve genes known as resistance (or R) genes that detect specific molecules produced by the microbe. These genes have been widely used in the breeding of wheat and other crops to improve disease resistance. However, this form of resistance can quickly become ineffective as the microbes mutate or lose the gene(s) that make the molecules detected by the R genes. So, the search is on for more durable forms of resistance. Continue reading

Book review: The Ash Tree by Oliver Rackham

Image by the author.

Image by S. Shailes.

In The Ash Tree, Oliver Rackham writes about the rich history and ecology of the European Ash (Fraxinus excelsior). One of the commonest trees in the UK, ash provides a home to many other species of wildlife and has long been used by humans for fuel, building, and for making wheel rims, ploughs and tools.

Amazingly, Rackham wrote the first draft of this book during a short hospital stay in Texas, drawing on his extensive knowledge of trees and woodlands without any notes to hand (the facts were double-checked later). Written in response to increased interest in ash when ash dieback disease hit the headlines in the UK, Rackham discusses this disease and other threats to ash including deer grazing and the emerald ash borer beetle. Drawing on other examples of tree diseases, Rackham argues that our current practice of transporting trees and wood products around the world is the biggest single threat to all our trees because it exposes them to new pests and diseases they have little or no resistance to.

I really enjoyed reading this book and would highly recommend this book to anyone with an interest in trees, woodlands or plant pathology.

The Ash Tree was published by Little Toller Books in 2014 Find out more: http://littletoller.co.uk/bookshop/monographs/ash/

I’ve recently written about the potential threat to ash trees from the emerald ash borer beetle, which is currently causing devastation to North American ash trees and is now marching into Europe from Russia. Read more here.

I’ve also written about how Ash Dieback disease is affecting an ancient woodland in my local area.