Eranthis hyemalis is a tuberous, herbaceous perennial that is native to the deciduous woodlands of continental Europe, naturalised over parts of the United Kingdom and a favourite, mid-winter-flowering garden plant. By the middle of spring, all the plant's above-ground parts have died back to the underground tuber. The phenology displayed by this species takes advantage of low interspecific competition and high levels of light reaching the woodland floor early in the year. The English herbalist John Gerard asserted that the deeper the snow from which the plant emerged the larger its flower. The generic name ('spring flower') and specific epithet ('of the winter') refers to the plant's early flowering.
The bright-yellow flowers have a collar of green, leaf-like bracts beneath them. However, the yellow, petal-like structures are not petals, they are sepals. The petals are the small, bucket-like structures that form a ring between the sepals and the numerous stamens. These structure are nectaries, and along with the sepals, attract and reward the few pollinators likely to be on the wing so early in the year. The carpels are unfused, and mature into fruits called follicles which contain several, large, brown seeds.
In the Oxford Botanic Garden in the mid-seventeenth century, there was a January-flowering plant growing called 'Aconitum hyemale', with the common name 'Winter wolfesbane'. This plant can be positively identified as Eranthis hyemalis because Jacob Bobart the Younger and his father, the first two Keepers of the Garden, made herbarium specimens which have survived to the present day. Gerard also called the plant 'English woolfesbane', implying it was a British native. Gerard goes on to explain why he calls it an aconite; apparently this is because of the shape of the leaves and the fruits, and plant's apparent toxicity. He also tells a curious tale of how the winter aconite is effective against the sting of scorpions - perhaps this is a reference to the form of the fruit and an example of the Doctrine of Signatures.
As a member of the buttercup family, one might expect winter aconite to be toxic, and indeed there is much anecdotal data to support this view. However, there appear to be no specific poisoning cases.
One of the most commonly planted winter aconites is a sterile form with aborted anthers and many carpels, sometimes called 'Guinea Gold'. This plant is sometimes also treated as a hybrid known as Eranthis x tubergenii.
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