Any of certain flowering plants of the genera Lythrum and Lysimachia, which are in different taxonomic families.
1919, Ronald Firbank, Valmouth, Duckworth, hardback edition, page 91,
He had a suit of summer mufti, and a broad-brimmed blue beaver hat looped with leaves broken from the hedgerows in the lanes, and a Leander scarf tucked full of flowers: loosestrife, meadowrue, orchis, ragged-robin.
2013, Théodore de Saussure, Jane F. Hill (translator), Chemical Research on Plant Growth, [Recherches chimiques sur la Végétation], page 22,
I grew some peas, loosestrifes, and fleabanes [“inules”] in profound darkness, beneath two identical receptacles filled with atmospheric air.