Dense, taller annual communities (usually up to maximum height 100 cm) colonizing nitrogen-rich muds of dry ponds and lakes of the boreal and nemoral zones of the Palaearctic, and locally of the Eurasian steppe zone. Dominants are Bidens spp., Rorippa palustris, Rorippa islandica, Chenopodium spp., Polygonum spp., Rumex maritimus, Rumex palustris, Ranunculus sceleratus, Senecio congestus, Catabrosa aquatica and Leersia oryzoides.