Euphorbia palustris

Euphorbia palustris (marsh spurge or marsh euphorbia) is a species of flowering plant in the family Euphorbiaceae, native to marshland throughout much of mainland Europe and western Asia. It is an herbaceous perennial growing to 90 cm (35 in) tall and wide, with narrow leaves turning red and yellow in autumn, and persistent, bright acid yellow flower-heads (cyathia), 15 cm (6 in) across, in spring.