How to identify Cardamine Species?

Cardamine has compound leaves with all its leaflets originating from different points. They are called Pinately compound leaf. The leaflets are arranged in an alternative arrangement. Can the Cardamine species be identified by leaflet arrangements?
We also found Cardamine has Racemose inflorescence.
Cubists are trying to learn how to find out species of Cardamine?

There is also popular saying that Cardamine plants have consistent features without much difference in species. We need to know species characters of Cardamine. Smaller differences are being said to not be species characters. Can we breed two similar looking Cardamine plants to know if they belong to same species?