Viola palustris
Glencoe mountains, Scotland.
Confirmed with species list here:
https://www.glencoewood.com/index.php/glencoe-wood/species-list/
I have deleted previous posting with lower quality pciture and wrong species. Still not 100 % sure this is the correct one, correct me if I am wrong :-)
''Viola palustris'' is a perennial forb of the genus ''Viola''. It inhabits moist meadows, marshes, and stream banks in northern parts of North America and Eurasia. The species epithet ''palustris'' is Latin for "of the marsh" and indicates its common habitat.
''Viola palustris'' is a 5 to 22 cm, glabrous herb with petioles and peduncles from slender rhizomes. The cordate to reniform leaves are 2.5 to 3.5 cm wide with coarse, shallow, blunt teeth. Petioles are 2 to 17 cm. The white.. more