Cuckooflower (Cardamine dentata), fam. Brassicaceae.
Occurs along the lakesides in the forest. Its leaves are not showy, so Cuckooflower is most notable in May, when it blooms with quite large white flowers with sweetish smell.
Amazingly, this blooming has almost no sense for the plant – Cuckooflower does not propagate from seeds. Instead, it prefers vegetative propagation, from leaf pieces with adventitious buds (like the indoor Kalanchoe plant).