Scientific name: Mercurialis perennis
Dog's Mercury is a woodland plant found in much of Europe. It is a herbaceous, downy, foetid perennial with erect stems to 40 cm bearing simple, serrate leaves. The dioecious inflorescences are green, bearing inconspicuous flowers in March and April. It characteristically forms dense, extensive carpets on the floor of woodlands and beneath hedgerows.
Dog's Mercury favours alkaline (basic) soils and can be found in abundance in suitable habitats in limestone regions. It also occurs widely on neutral soils, but is absent from acidic ones. It thrives in deep shade or semi-shade, but eventually gives way to other plants in the open. It does not easily colonise new sites, and so is strongly associated with land which has had a long continuity of woodland or shrub cover. For this reason it rarely occurs in extensive areas of secondary woodland.
Dog's Mercury is poisonous.
Information and photographs courtesy of en.wikipedia.org