There are two sub-types of tall herb fen recognised in the UK; tall herb-dominated and what is known as ‘tall herb/swamp transition’. The image here shows the tall herb-dominated form which typically comprises a mix of co-dominants over 1m tall, such as greater willowherb (Epilobium hirsutum), meadowsweet (Filipendula ulmaria) and wild angelica (Angelica sylvestris). This type of tall herb fen forms a transition between grassland and true fen and swamp habitats.
The tall herb/swamp transition is quite dense and wet, with some water visible. The flora typically comprises one or two of the typical species that dominate true swamps but with a small number of tall herb species persisting, making the vegetation more species-rich than true swamp habitat. The typical tall herb species could include marsh cinquefoil (Potentilla palustris) common nettle (Urtica dioica), branched bur-reed (Sparganium erectum) and water mint (Mentha aquatica).