|Close-up on flowers of Lysimachia clethroides|
Lysimachia clethroides, common name gooseneck loosestrife, is a species of flowering plant, traditionally classified in the family Primulaceae, but belonging to the family Myrsinaceae, according to a molecular phylogenetic study. 
Lysimachia clethroides can reach heights of 60–100 centimetres (24–39 in). This hardy herbaceous perennial resembles a tall Speedwell. The stem is upright and rigid. The leaves are scattered, alternate, oblong or broadly lanceolate, about 2 inches wide, 7 to 11 centimeters long, with entire margins. The flowers are tiny (1/2" wide), grouped in terminal spikes, each flower being snow white, with five petals. The inflorescence is bent with a sparsely haired axis, reaching a length of 12-18". It flowers throughout summer. This plant forms underground stolons. It is a pioneer plant in its natural range.
Distribution and habitat
The native range of this plant is China and Japan. It is also found in Russia, Korea and North America. It is present in damp woodland margins, in wet ravines and forests, in sunny grassy hills and mountain slopes at elevations of 300–2,100 metres (980–6,890 ft) above sea level. It prefers deep, rich loam and sheltered positions.
- M. Källersjö, G. Bergqvist & A. A. Anderberg (2000). "Generic realignment in primuloid families of the Ericales s. l.: a phylogenetic analysis based on DNA sequences from three chloroplast genes and morphology". American Journal of Botany (American Journal of Botany, Vol. 87, No. 9) 87 (9): 1325–1341. doi:10.2307/2656725. JSTOR 2656725. PMID 10991903.
- Harrison, Lorraine (2012). RHS Latin for gardeners. United Kingdom: Mitchell Beazley. p. 224. ISBN 9781845337315.
- "RHS Plant Selector - Lysimachia clethroides". Retrieved 22 May 2013.