(Veronica beccabunga) European speedwell

Veronica beccabunga, the European speedwell or brooklime, is a succulent herb belonging to the family Plantaginaceae. It grows on the margins of brooks and ditches in Europe, North Africa, and north and western Asia. It can be found on other continents as an introduced species. It has smooth spreading branches, blunt oblong leaves and small bright blue or pink flowers.

The species name beccabunga comes from Danish bekkebunge (literally "brook bunch") or a similar source. 

Medicinal usage
Brooklime was one of three traditional antiscorbutic herbs (alongside scurvy grass and watercress), used in purported remedies for scurvy. However none of these herbs are rich in vitamin C and the usual preparation by extracting of juices would have destroyed most of their content, rendering the preparations ineffectual against true scurvy.
en.wikipedia.org

https://en.wikipedia.org/wiki/Veronica_beccabunga