Every Wednesday, I hope to find a new ‘weed’ to investigate. My only criterion will be that I will not have deliberately planted the subject of our inquiry. Who knows what we will find…..
Dear Readers, this week our subject, bristly oxtongue, is a truly ‘weedy’ weed, a plant of rough ground and disturbed soil. As its name suggests, it is a plant whose leaves are covered in swollen, blister-like spots. From each blister a little hairy hook emerges, which makes it as rough as ‘an ox’s tongue’. As I have never been licked by an ox, I cannot verify the accuracy of the plant’s name, but as that bovine organ is used for tearing up harsh grasses, I can imagine that it would need something hook-like to give some traction. At any rate, these little blisters are indicative that, amongst all the yellow-flowered members of the daisy family, we are looking at bristly oxtongue.
Bristly oxtongue is an ‘ancient introduction’ – this means that it arrived in the UK before 1500. It has also found its way to North America, where it has quickly become a member of the Invasive Weeds lists of several states. The plant is originally from the Mediterranean, which suggests that it could have arrived into the UK with the Romans, possible secreted away in grain stores. However, there could be another reason that this somewhat unprepossessing plant ended up here, and the clue is in its genus name, Helminthotheca. ‘Helmine’ refers to worms, and while it could be a reference to the shape of the fruit, it is more likely that bristly oxtongue was used as a treatment for intestinal worms. Whether the bristles acted as a kind of internal scouring pad, or whether there was some chemical attribute is unclear.
Bristly oxtongue is so prevalent in Buckinghamshire that it has been given the nickname ‘Milton Keynes Weed’. It is also known as ‘Langley-Beef’, a corruption of the French ‘langue du boeuf’ (oxtongue). Although the young leaves are said to be edible, they look as if they would be rather problematic, what with all those spines and blisters, and I suspect you’d be better off sticking to dandelions for your salad.
Like many plants in the daisy (Asteraceae) family, bristly oxtongue provides nectar for visiting butterflies and moths, and cover and food for many other invertebrates, such as the tiny beetle in the photograph below. This little creature was as shiny as a drop of mercury, and is, I think, some kind of flower beetle – we think of bees and butterflies when we think of pollinators, but flies and beetles also perform an important role.
Why, I wonder, does the bristly oxtongue have bristles in the first place? Most structures of this kind have developed to deter grazing animals, and I suspect that this is part of the story here too. But why is this plant so well protected, compared to all the hawkbeards and dandelions and sowthistles to which it is so closely related? The only clue that I can find is that unlike many other plants in the family, bristly oxtongue has very sparse sap. Anyone who has snapped the stem of a dandelion knows that it will quickly ooze a prolific and rather unpleasant white latex-like liquid, which is surely unpleasant to eat. Maybe the bristles have developed as a deterrent because the sap alone would not be enough. Who knows? But one thing that I do know is that, although the leaves are ugly to our eyes, the flowers, with their stamen like little calligraphy-squiggles, are a welcome food-source for passing creatures of all kinds, who notice them as even as we pass by without a second glance.
Leaf hair macro photo by Derek Lilly (https://creativecommons.org/licenses/by-nc-sa/2.0/legalcode). More of his photos here (Jusben on morguefile.com)
Harford’s Sulphur Butterfly on Bristly Oxtongue by By Davefoc (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons