Mercurialis perennis
 Mercurialis perennis commonly known as dog's mercury is a woodland plant found in much of Europe but almost absent from Ireland Orkney and Shetland. A member of the spurge family (Euphorbiaceae) it is a herbaceous downy perennial with erect stems 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.