A crimson-flowered plant of the family Scrophulariaceae, Pedicularis palustre, found in marshes and damp meadows in Europe (also called red rattle or marsh red rattle).
Origin
Mid 18th century.
Definition of marsh lousewort in US English:
marsh lousewort
noun
A crimson-flowered plant of the family Scrophulariaceae, Pedicularis palustre, found in marshes and damp meadows in Europe (also called red rattle or marsh red rattle).