Comarum palustre

About

Comarum palustre, known by the common name marsh cinquefoil, also purple marshlocks and swamp cinquefoil, is a waterside rhizomatous subshrub. It has a circumboreal distribution, occurring throughout cool temperate Asia, Europe, and North America, particularly in northern regions. It is most commonly found on lake shores, marshy riversides and stream margins, often partly submerged with foliage floating. It is a parent of some Fragaria–Comarum hybrids, ornamental plants produced by crossing with strawberries.

Summary from Wikipedia