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, I am sure that when you were children many of you, like me, will have picked a buttercup and held it under your chin to see if you ‘liked butter’, a most nonsensical way to carry on but an experience which, in these parts at least, seems to be almost universal. However, you would have difficulty performing the exercise with this buttercup, which I noticed in the cemetery last week. Although it has the leaves of a buttercup, and although the buds look familiar, the flowers are very strange. The petals look somehow stunted, as if they’ve been nibbled off by a famished caterpillar. And yet, it appears, this is a characteristic of the Goldilocks buttercup (Ranunculus auricomus), a plant in which almost every flower is deformed.
Why ‘Goldilocks’, I wondered? Well, the species name auricomus literally means ‘golden-hair’, so maybe the English name is an exact transliteration. Or, as someone suggested, maybe its woodland habitat put people in mind of the fairy story. Whatever the reason, it is a strange and delicate plant, all stem and stamen.
This species loves chalk (technically, it is a calcicole, another new word!) I was therefore surprised to find it growing in the heavy clay of the cemetery. However, every patch that I’ve found has appeared directly on top of a grave, so maybe something in the planting medium is subtly different, enabling the buttercup to thrive.
The Goldilocks buttercup reproduces asexually (known as apomixis) – it sets seed without need for cross-pollination, and every new plant is a clone of the parent. This means that there can be unique local populations, known as agamospecies, and several hundred of these have been identified in mainland Europe, though, as far as I know, no one has looked into the situation in the UK yet. Our growing expertise with genetic analysis has opened a whole can of worms with regard to plants. Once, a dandelion was a dandelion, but now there are known to be 40 endemic microspecies in the UK alone. It seems that no sooner do we clear up one mystery than hundreds more present themselves. Still, what an exciting time to be a geneticist!
The Goldilocks buttercup is native to the UK, and has a range that extends from Greenland (where it is sometimes found growing in the damp places beside waterfalls) right the way through northern Europe and Russia, and then into Alaska and the Western US. For this reason, the plant is sometimes known as the Greenland buttercup. However, it is slow to spread locally, and is seen as an indicator of ancient woodland. Were these buttercups growing in the woods that pre-date the cemetery, I wonder?
I wonder, too, about those deformed and missing petals. As the plant reproduces asexually, maybe the need to attract insects for pollination is not as strong as in other buttercups. Could it also be because, as each plant is a clone, any damaging genes will perpetuate themselves? In his book ‘Vegetable Teratology’, Maxwell T. Masters mentions that in damp woodland settings, the Goldilocks buttercup tends to have small, distorted petals and luxuriant leaf growth, but in more arid sites the petals are more complete, the leaves smaller. It’s almost as if the plant has a ‘growth budget’, which it expends according to the situation in which it finds itself. At any rate, the lack of petals doesn’t seem to have done these plants any harm, as they were growing in some numbers in the shade of the old hornbeams, surrounded by their close relatives the Lesser Celandines (Ranunculus ficaria).
What an unusual plant this is! I am used to seeing flora with all manner of galls and discolourations, their leaves nibbled and mined by their insect hosts (as are some of the leaves in the photograph below). I am familiar with the range of colours that can occur within even a small population of the same plant. And yet, I have never come across one before with distorted or absent petals through no obvious external cause. It just goes to show that nature is full of surprises.