This association includes open low-growing stands of wetland annual herbs. It was recorded on sandy substrates in fishpond margins and on the bottoms of fish storage ponds. The diagnostic species of this vegetation unit require a constantly wet substrate at least until the time of flowering, and sometimes the habitat is flooded by shallow water. This association was probably always rare in the Czech Republic, but it retreated from most of its historical localities (especially in the Třeboň Basin) due to eutrophication and intensification of fishpond management. Both historical and recent localities are concentrated in southern Bohemia.