Nature to look out for in Burwell

Back in April I wrote about bulbous buttercups, that at the time were flowering along the paths and grassy areas of Burwell. At the time I said there are three common species of buttercup found around the village and I frustrated some of you by not describing the other two species. So I will make up for my error now, with my apologies. Bulbous buttercups are finished flowering now, the other two species – creeping buttercups and meadow buttercups – are flowering well – creeping buttercups too well for allotment holders, where they are constantly creeping off the paths into the vegetable growing patches!

First a quick reminder about Bulbous buttercups. You may remember these are easily told from the other two species of buttercup as their sepals – petal-like structures under the petals – fold downwards towards their stems. Sepals are usually not as showy as a flowers’ petals – which are often brightly coloured to attract pollinating insects – but they play an important protecting role, often sheltering the petals when the flower is in bud or during rain.

Creeping buttercups Ranunculus repens are well named for those who regard them as a menace. Their leaves form thick mats, crowding out other vegetation and as their name implies, they creep – by sending out runners that then root. In this way they quickly and literally, gain ground. They tend to flower low to the ground and their leaves are less intricately edged than the other two buttercups and often have pale blotches.

Meadow buttercups are the ballerinas of the three. They stand tall, have elaborately cut leaves and grow where habitat is at its finest for wildlife. I’ve seen a few in Priory Wood and at Burwell Castle; they are rampant at Pauline’s Swamp.

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In evolutionary terms, buttercups are one of the oldest flowers. You can tell this by their simple form: they have petals that are separate to each other and multiple male stamens, which circle the inner female stigmas. To be fertilised pollen from a stamen needs to transfer to a stigma, where it travels down a thin tube to the ovary below. The stamens and stigmas on any one flower are fertile at different times to avoid self-fertilisation. Buttercups have a simple strategy for reproduction. The wide open flower aims to attract insects to land. The presence of multiple sexual organs increases the chances of an insect picking up pollen from the anthers, or transferring pollen to the stigmas.

As flowers evolve, their strategy becomes more developed. Petals fuse, creating funnels to draw pollinating insects in. As the strategy for drawing in the insects right into the flower improves, the numbers of stamens and stigmas can reduce, – so reducing the energy costs for the plant. The beautiful bluey-purple tall viper’s-bugloss is in flower now. Look at how clever this species’ flower is. As a bee lands on a lower petal attracted by the prospect of a drink of nectar, the other petals bend and the male stamens brush round the bee, to ensure the bee picks up pollen to carry to and fertilise the next viper’s bugloss flower it visits. To reach the nectar, the bee has to put its head right into the flower. Any pollen it is carrying from another flower has ample chance of being brushed off onto this flower’s female stigmas. The ova in the heart of the flower is fertilised and a seed is formed.

I found learning I could have an idea of a flower species’ place in the evolutionary process just by looking at its structure a revelation. Have a look at all the plants in flower now and see how much they have adapted to attract insects in, to save themselves costly energy and be as effective as possible at reproducing. We are looking at the result of millions of years of development – and also know, when we look at buttercups, we are going back to the very earliest times. In french they are called bouton d’or, buttons of gold. Indeed they are.

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