Winter Aconite, Eranthis hyemalis
Winter Aconites are one of the first plants to flower in Spring. This photo was taken whilst on a visit to Slimbridge in February 2017.
It is not a native British plant but it is native to France, Italy and the Balkans. However it has become naturalised in some areas and has been known in the wild since the 1830s. It is widely planted in gardens and parks, but also naturalised when it can form extensive patches in woods, grass, parkland and open areas. Reference to the distribution maps from the National Biodiversity Network Gateway indicate that it is not found in my local patch, the Wye valley, however I am sure someone will know somewhere where it occurs. In France it is found in more alkaline, chalky districts. In the UK it is scattered throughout the country but is mainly in the South Midlands, the Southeast and the East.
It is a member of the Buttercup family but is more related to Monkshood (also in the buttercup family) and is similar to this plant in that it does contain a variety of poisonous substances although the toxins are not the same ones as in Monkshood. They are called Glycosides.
Winter Aconite contains several cardiac glycosides of the chromenone type such as Eranthin A and Eranthin B. It also contains another four different 4H-Chromenone Glycosides. They all exhibit negative inotropic activity. Ingestion of substantial quantities leads to symptoms of poisoning by cardiac glycosides: nausea, vomiting, diarrhoea, colic, bradycardia, disturbed vision, dyspnoea and finally cardiac arrest. So do not munch on them.
Shown above is Eranthin only, but not with any glycosides attached to it.. The glycosidic groups will be attached where the hydroxyl ion is, replacing the hydrogen atom with a glycoside, or more in a chain of glycosides. Chromenones such as this are presumably brightly coloured. Interestingly, a similar poison is also present in the secretions from toads skin.
The plant reproduces in two ways, it has tuberous roots and this is how it overwinters but also slowly spreads. The flowers do produce seeds which can lead to a more rapid spread. The yellow flowers are held above a circle of green bracts that could be confused for sepals. Next come a ring of six yellow sepals, which you would assume were the petals. The petals are reduced to small tubular nectaries. There are quite a large number of yellow stamens and just six carpels.
To check out other wildflowers found in the woods of the Wye valley and Ninewells wood click Woodland Wildflowers of the Wye valley and Monmouthshire.