Chamomile (Anthemis), fam. Asteraceae.
A low daisy-like flower, blooms in May. It is widespread as a drought-resistant, unpretentious weed along the railways.
In other parts of Ukraine, there is also Dyer's Chamomile (Anthemis or Cota tinctoria) with yellow petals (last photo). It has not been observed in Kyiv. Chamomile is used in folk medicine to treat liver diseases, as a sudorific, antipyretic and blood-stopping remedy. Yellow dye was extracted from Dyer's Chamomile flowers, to color the woolen clothes. Dried inflorescences might be used to protect clothes from moth. The plant has potentials to be grown as ornamental.