Caltha palustris (Kingcup, Marsh Marigold) is a herbaceous perennial plant of the buttercup family, native to marshes, fens, ditches and wet woodland in temperate regions of the Northern Hemisphere. In the UK, Caltha palustris is known by a variety of common names, varying by geographical region. These include Marsh Marigold and Kingcup (the two most frequently used common names), Mayflower, May Blobs, Mollyblobs, Pollyblobs, Horse Blob, Water Blobs, Water Bubbles, Gollins. Balfae (in Caithness) and the Publican. The common name of marigold refers to its use in churches in medieval times at Easter time as a tribute to the Virgin Mary, as in Mary gold.