Lysimachia vulgaris

Lysimachia vulgaris, commonly called yellow loosestrife or garden loosestrife, is a herbaceous perennial flowering plant in the family Primulaceae and order Ericales; it was previously classified in the subfamily Myrsinoideae before molecular phylogenetic research merged that group into Primulaceae. The species is native to Eurasia, common as far west as Ireland, and also found in North Africa; it has been introduced to North America as an ornamental plant and is now considered invasive in Washington State and Oregon. It is a tall, downy, semi-evergreen perennial reaching 50 to 150 centimeters high, with erect clusters of conspicuous yellow flowers, opposite or whorled leaves 5 to 12 centimeters long spotted with orange glands, and stems that are downy and round or square in cross-section. In the British Isles it flowers from June through August.