With one thing and another I’ve managed three walks to Cassop this month, in a range of different weather conditions, sometimes all four seasons in the course of one walk! There is still little to see in flower – for the most part the yellows have it; Hazel, Willow and Alder catkins along with Gorse and Lesser celandine.
A few hardy daisies are in flower and, by the end of the month, the first Wood anemones have appeared in the woodland above the valley.
Lesser celandine is one of my favourite harbingers of spring, though I know not everyone feels the same. It can carpet woodland floors, reducing growing opportunities for less robust species and is regarded as an invasive weed in N America. However, in the UK it is an important nectar source for queen bumblebees and other insects which emerge early from hibernation. One unusual feature is the variability of its flowers. Books such as Rose’s Wild Flower Key will tell you it can have anything between eight and 12 glossy yellow petals on each flower but a quick survey soon shows it can have even more! Double flowered strains appear naturally in the wild but have also been selected for by horticulturalists. It’s a difficult plant to photograph well – the glossy sheen on the petals acts not only to attract pollinating insects but to reflect light and heat onto the central reproductive parts of the flower and speed up their growth (Van der Kooi et al., 2017).
Now called Ficaria verna (rather than its old name of Ranunculus ficaria), Lesser celandine remains a distinctive member of the buttercup family, with its multiple unfused carpels (the female reproductive structures) and surrounding thick wreath of stamens and anthers (which carry the pollen). The unfused carpels are a sure sign of a flowering plant with a long evolutionary history, which arrived on the scene something over 100 million years ago.
Lesser celandine is one flower you really only notice when it’s sunny – the flowers, like so many others, close at night but can also open and close several times during the day (something known as nyctinasty), depending on whether they are in sunlight or shade. The green undersides of the petals make the flowers much less visible when closed and help protect the valuable reproductive parts of the flower from slugs and other hungry herbivores, which are generally most active at dawn and dusk. There is, of course, a trade off – when the flowers are not open, pollination can’t take place (self pollination is not common).
In an intriguing little paper published in 2016, Pavol Prokop and Peter Fedor describe placing wire loops on top of open Celandine flowers to stop them from closing at night. This seemed not to affect the number of seeds produced by the flowers which survive but did make them more likely to be grazed. As other food is scarce when celandines flower, it seems to be worth the energy needed to open and close the flowers and risk reduced rates of pollination to protect the reproductive parts. Prokop and Fedor’s study didn’t attempt to show whether flowers close in dull conditions to avoid the possibility of damage by rain, as has also been suggested. Another possibility is that a closed flower keeps the carpel and anthers warm when it’s not sunny – it may all be part of speeding up the process of seed set at a time of year when air temperatures are still relatively low.
I’m not the only one to see celandines as a potent symbol of spring. Wordsworth wrote three poems in praise of them, going so far as to suggest that the way we depict the sun ‘with pointed rays’ comes from celandine flowers bursting out in spring. When he died, a celandine was carved on his memorial plaque inside St Oswald’s Church in Grasmere but unfortunately the stone mason was no botanist and carved an unrelated Greater celandine, Chelidonium majus (from the poppy family) instead!
In an equally-universal picture, Edmund sees “the ground covered in all directions with little yellow flowers – celandines”, when Aslan’s return turns perpetual winter into spring in C.S. Lewis’ The Lion the Witch and the Wardrobe.
Geoffrey Grigson has Lesser celandine going by the charming name of Pilewort because, according to the ‘Doctrine of Signatures’ its tuberous roots look like haemorrhoids. I prefer the traditional Somerset name of ‘Spring messenger’! Some sources report the leaves as being high in vitamin C and used to prevent scurvy but this seems likely to be a case of mistake identify – the fleshy leaves look quite like those of common Scurvy grass, Cochlearia officinalis, which really was dried and carried on board ships in the 18th and 19th centuries.
As with others in the buttercup family, damaged leave of Ficaria verna actually produce a skin irritant and toxin called Protoanemonin, though heating or drying the leaves converts this to non-toxic anemonin – personally I think there are more pleasant ways to get my Vitamin C.
The highland cows are still in residence at Cassop but the ground is drying out fast and is now studded with leafy rosettes of Primula and other species, as well as seedlings which look horribly like Himalayan Balsam to me – I hope to be proven wrong about that. By next month things will be much clearer.
Grigson, G. (1958) The Englishman’s Flora
Prokop, P. & Fedor, P. (2016) Why do flowers close at night? Experiments with the Lesser celandine Ficaria verna Huds (Ranunculaceae). Biological Journal of the Linnean Society, 118, 698–702.
van der Kooi, C.J., Elzenga, J.T.M., Dijksterhuis, J. & Stavenga, D.G. (2017) Functional optics of glossy buttercup flowers. J. R. Soc. Interface 14: 20160933. http://dx.doi.org/10.1098/rsif.2016.0933
Wordsworth, W. (1802) To the Small Celandine