The Marsh marigold or Kingcup, Caltha palustris, is a British native, producing large buttercup flowers in spring. It is ideal for a bog garden or he edge of a pool. There are related species from elsewhere, some with yellow and some with white flowers.

Caltha scaposa is a species from the Himalaya and China, rather like our marsh marigold, Caltha palustris, but it is much more compact. The bright yellow, cup-shaped flowers grow just one to each of the stems, which rise directly from the heart-shaped leaves, which in turn lie almost flat on the ground. Easy in a suitably damp place.