dog's mercury

Plant belonging to the spurge family, common in woods of Europe and southwest Asia. It grows to 30 cm/1 ft, has oval, light-green leaves, and spreads over woodland floors in patches of plants of a single sex. Male flowers are small, greenish yellow, and held on an upright spike above the leaves; female flowers droop below the upper leaves. (Mercurialis perennis, family Euphorbiaceae.)