Dandelions (Taraxacum officinale) are so common that they are easy to take for granted; but look closer and you will see an amazing organism (perhaps even a super-organism) so well adapted to reproduce and spread, it is hard to believe that they will not be here long after we have moved on!
Dandelions pop up each year from roots in the ground, up to ten stems from each little root. The dandelion head is composed of a composite of tiny little florets, over 100 florets per flower head. These florets are bisexual – the dandelion is a hermaphroditic plant – but although they produce pollen, funnily enough it is not necessary for reproduction of the plant. Dandelions are able to produce seeds without having to be fertilised – by a process called apoxixis (1). Some dandelions however, are sexual, meaning that they rely on being fertilised by pollen carried from one dandelion to another by insects such as bees. So there are both sexually reproducing and asexual – or apomictic – populations of dandelions mixed up together. Whatever way they do it though, dandelions produce masses of seeds – over 100 florets per flower head – which can add up to millions per hectare, all ready to be blown away on their little parachutes to some nice disturbed patch of ground where they can grow into a new dandelion on their own!
But remember, the asexual ones will carry the same genes as their parents, so they will be identical: a clone in fact. All of these clones could be seen as the same organism, or super-organism. Other authors have compared each individual plant clone to leaves on the same tree. So, although they may be separated in space and time, all the clones constitute a giant organism that is spreading and reproducing itself all the time.
1) Chapter 22. An Apomixis-Gene’s View on Dandelions. Peter Van Dijk, Hans de Jong, Kitty Vijverberg and Arjen Biere. In I. Schön et al. (eds.), Lost Sex, DOI 10.1007/978-90-481-2770-2_22, 475, Springer Science+Business Media B.V. 2009. http://joelvelasco.net/teaching/167win10/van%20dijk%20-%20an%20apomixis%20genes%20eye%20view%20of%20dandelions.pdfflower
I am an entomologist with a background in quarantine pests and invasive invertebrates. I studied zoology at Imperial College (University of London) and did a PhD on the population dynamics of a cereal aphid (Metopolophium dirhodum) in the UK. I spent 5 years with the British Antarctic Survey studing cold hardiness of Antarctic invertebates and 17 years with the Food and Environment Research Agency. My main interests now are natural history, photography, painting and bird watching.