a cosmopolitan genus of plants, including some of the loosestrifes, found in damp or swampy terrain having usually yellow flowers; they are inclined to be invasive.

Lysimachia is a genus of flowering plants. It is traditionally categorized in the family Primulaceae but should, according to Källersjö et al (2000), belong to the clade of the family Myrsinaceae.

Lysimachia (in Greek Λυσιμαχια or Λυσιμαχεια) was an important hellenistic Greek town in European Turkey on the north-western extremity of the Thracian Chersonese (the modern Gallipoli peninsula), not far from the bay of Melas (the modern Gulf of Saros). It was built by Lysimachus in 309 BC, when he was preparing for the last struggle with his rivals; for the new city, being situated on the isthmus, commanded the road from Sestos to the north and the mainland of Thrace. In order to obtain inhabitants for his new city, Lysimachus destroyed the neighbouring town of Cardia, the birthplace of the historian Hieronymus.