One of my favourite sights in spring is a meadow full of buttercups.  These golden grasslands brighten up even the greyest days but the cold spring this year has meant that they are created from a mixture of up to four different species.  In normal years there is a succession of flowering, starting with Goldilocks, followed by Bulbous, then Meadow and finally they are joined by the Creeping Buttercup but this year they are all out together making it a great opportunity to hone your buttercup identification skills

The name 'buttercup' is applied to the yellow-flowered Ranunculaceae species that favour drier habitats as opposed to 'spearworts' which are normally found in wet places and pond margins.  In addition to the four commoner buttercup species there are three other much scarcer species found in the UK.  Of these, according to the BSBI atlas, the Small-flowered Buttercup is the only one that is shown to be present in Montgomeryshire but as it has a preference for bare and dry places on lime rich soils, it is unlikely to be seen in many of our local grasslands.  Another buttercup, the Cornfield Buttercup, used to be a widespread weed in arable fields but over the last few decades, due to modern farming practices, has seen a dramatic decline. 

The story of Goldilocks

The Goldilocks Buttercup (Ranunculus auricomus agg.) has petals that are lax and much more open than the other common buttercup species creating a golden yellow ring of petals around the flower centre.  This is probably the basis for the common name as well as the Latin name ‘auricomus’ which means ‘golden haired head’.  This species is more often found near hedgerows and in woodland edges than in the middle of meadows and is considered a good indicator for species rich habitats and long-established woodlands.  Being one of the first buttercups to flower it has usually completed growth and set seed by the time the trees are in full leaf which is probably an adaptation to its preferred shady habitats and it also lacks the acrid toxins found in other buttercups making it more at risk of browsing by herbivores.   

Goldilocks flowers often have one or more missing or deformed petals, making them appear a bit dishevelled and this is often an easy way to identify them.  However, a lot of the specimens that I have seen locally have well-formed flowers and it is the slender stems and long, narrow leaves at the base of the flower stem that are more diagnostic.  Goldilocks is also unusual in that it is apomictic (meaning that reproduction is asexual without fertilization), and although the flowers do appear to have anthers and pollen, no pollination occurs and this may explain why deformed or missing petals do not cause it any problems.  In addition, there are reportedly over 200 microspecies (agamospecies) in the UK so any plant that you find is generally considered to be part of a visually indistinguishable aggregation.  So, in conclusion, the Goldilocks is an often overlooked but surprisingly unusual plant.

The bulbous one

The Bulbous Buttercup (Ranunculus bulbosus) is probably the easiest buttercup to identify as the flowers have what is termed ‘reversed’ sepals, where rather than the sepal lying under the petals, they are turned backwards and point down the flower stem.  It is also relatively short (usually less than 25cm tall) and flowers within the canopy of spring grasses such as Sweet Vernal-grass.  If you were to dig one up (please don’t!) you would find that, just below the surface, it has a bulbous stem base which stores nutrients and helps the plant to grow rapidly in the spring and reach peak flowering before the Meadow Buttercups

The tall one

Meadow Buttercups (Ranunculus acris) are the giants of the buttercup world and can grow up to 100cm in rich pastures, although more usually they are around 40 - 60cm tall, flowering well above the grass canopy.  The sepals are formed in a normal manner under the petals making it easy to distinguish them from the Bulbous Buttercup.  The leaves are palmate and deeply cut with the end lobe always unstalked which, together with the branched flower sprays, are the most certain way to distinguish it from a Creeping Buttercup.

The Latin name ‘acris’ suggests, this is one of the acrid species.  This acrid characteristic is due to the presence of a compound called ranunculin that breaks down when the plant is bruised to form a toxic oil called protoanemonin.  This oil can cause itching and burning along with rashes and blisters, and if ingested, can cause severe gastrointestinal irritation but it is unlikely that you will suffer any of these symptoms from casual contact with the plant.  This is all part of the chemical warfare practiced by plants to discourage herbivores from eating them but fortunately, if the plant is cut for hay or silage, the oil rapidly breaks down to an innocuous compound which is why it is not a problem to have an abundance of buttercups in hay meadows.

The creeping one

The Creeping Buttercup (Ranunculus repens) lives up to its name by producing rooting runners that can quickly enable it to colonise areas of bare soil in the garden.  It is also the buttercup most able to survive regular close mowing so if you have had a No-Mow May, you should have a beautiful crop of yellow cups of this plant by now.  In the wider countryside, Creeping Buttercup is more common on damper and richer soils as well as in areas of disturbance where it can form dense colonies.  Creeping Buttercups are often considered by gardeners to be a problem weed as they can quickly overwhelm a cherished flowerbed if left to do their own thing.  However, they are shallow rooted and easy to remove by weeding, and their golden yellow flowers in the lawn are pleasing to the eye as well as much loved by pollinators and other insects

Interesting fact:

The petals of buttercups have a thin layer of air trapped between the cells that is very efficient at reflecting light which is presumably to make them more visible to pollinating insects.  It is also probably the reason why it is sometimes difficult to get good photos of the flowers.

All that’s yellow is not a buttercup

Many other spring flowers are yellow and you might mistake them for a buttercup at first glance. Here are some that you might find in flower at the moment and some tips to help identify them.

I hope that this has encouraged you to look more closely at the yellow flowers around you and perhaps let the grass grow longer in your garden to see what you might have growing in your lawns

Happy wildlife watching

Tim

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Any views or opinions represented in this blog are personal and belong solely to the author and do not represent those of people, institutions or organizations that the author may or may not be associated with in professional or personal capacity, unless explicitly stated