Is there anything as cheerful as a lawn blanketed with dandelions? Dandelions are one of my favourite so-called weeds. The bane of gardeners and lawn purists, and the backbone behind an entire herbicide industry, this sturdy plant pops up just about anywhere. But it’s hard to feel antagonistic towards something so cheery.
I was shocked to discover that the incredibly common dandelion is in fact not native to North America. It’s originally a plant of Eurasia, but has been spread throughout virtually all temperate areas around the globe, in both northern and southern hemispheres. The species group evolved about 30 million years ago on its home continent; its presence here in the Americas is just a tiny blip in evolutionary time.
The name dandelion refers to members of the genus Taraxacum. There is some debate among scientists about just how many species are included in the group, with estimates for just the British Isles ranging from 60 to 250 species. I don’t know a whole lot about the taxonomy of plants, so I can’t comment on what they use to define a species. The definition we learned in school is that a species can’t mate with other species to produce fertile offspring (it either can’t mate in the first place, or the egg won’t fertilize, or the embryos abort, or the living offspring is infertile, like in mules). Of course, we know this isn’t always strictly true, but it seems like a pretty good rule of thumb, so I’m surprised at all the confusion. Perhaps the new genetic barcoding projects will help clear things up.
The name dandelion is a corruption of the French name “dent de lion”, or Lion’s Tooth, a reference to the jaggedly toothed leaves. This seems to have been a historical French name, as they no longer call them that. Instead, the modern French name for the plant is “pissenlit” – separated, “piss en lit”, which means, of course, “piss in bed”. I thought this was hilarious. Can you imagine a plant with a name like that here? It apparently comes from the plant’s diuretic properties when consumed. The Italians and Spanish have something similar, and an English folk name is “pissabed”.
Going a different route, locally in Veneto, Italy, they’re known as “pisacan”, meaning “dog piss”, referring to their common occurrence in such favoured places of dogs. Novara, Italy, and the Polish are much more refined, with their words both meaning “to blow”, a reference to the plant’s seed heads. In Hungary it’s known as “dog milk”, commenting on the pale sap that comes out when the stem is broken, or “child chain grass”, an observation on how children can make chains by removing the flower heads and inserting the narrow top part of the stem into the hollow bottom part.
Dandelions are members of the family Asteraceae, characterized by family members bearing flower heads that have many individual flowers. In the case of the dandelion the individual flowers are difficult to separate from each other. I’m unclear about whether each yellow “petal” represents a separate flower on these plants or not.
The leaves themselves grow in a rosette, from which one or multiple flower stems may grow. In low-growing, open areas such as lawns, the leaves can spread out and kill surrounding plants by preventing light from reaching them, however where they grow with vigorous competition the leaves are usually more vertical, and the plant can grow fairly tall. Dandelions have a monsterous taproot, which can make them a real challenge to pull out of the ground successfully. If you break off the taproot, the plant has the ability to regenerate from what remains in the soil.
You can see the pollen-producing organs here, the older of which seem to have split open. I’m not sure exactly what’s going on, whether this split releases more pollen, or what the situation is. I’m also not sure where the female organs are. I’m sure I could easily have turned up some webpages on dandelion reproduction, but to me that’s not the most interesting thing about these plants.
Dandelion pollen is collected by many insects, and many others come to the flowers for the nectar. When watching the flowers on my parents’ lawn I saw bees, wasps, flies and ants all visiting the plants. Once the seeds mature, they are eaten by seed-eaters such as goldfinches. There are quite a number of caterpillars that feed on the foliage.
Each fertilized ovary develops into a single seed, which is attached to the flower head. A small parachute of fine hairs grows from the seed, and carries it away on the wind. The seed head is called either a “clock” or a “wishie” – the latter, of course, being from the children’s game of making a wish as you blow the seeds off the seed head. The seeds can be carried some distance on the wind, but eventually will either settle to the ground when the wind dies, or be blown into an object, where the parachute breaks off and the seed drops to the ground. This is why you often see so many dandelions growing along the edges of walls or around the base of trees.
A single seed head can produce anywhere from about 50 to 175 seeds, depending on its size, and a plant can grow multiple seed heads. It has been estimated that some very dense stands of dandelions may produce up to 97 million seeds per hectare, or about 39 million per acre!
Dandelions are eaten in many places as a culinary dish. The dandelion greens can be served cooked or raw, much the way one would use spinach. Raw leaves have a slightly bitter taste, and usually only the young leaves and unopened buds are used in salads. Older leaves are generally cooked. They’re high in vitamins A and C, and contain more calcium and iron than spinach. Dandelion flowers can be made into a sort of wine, and the roasted taproot can be a coffee substitute. In the UK, a soft drink exists that is made from dandelion and burdock and is called, appropriately, “Dandelion and Burdock”.
Interestingly, Wikipedia also claims that the milky sap from the flower stem can be used as a mosquito repellant, though you’d have to clip a lot of dandelions to get enough to work, I’d think. It can apparently also be applied to warts as a wart remover, and other parts of the plant have historically been used for treatment of other ailments.