Marsh marigold

Marsh marigold (Caltha palustris)
Marsh marigold (Caltha palustris)
Marsh marigold (Caltha palustris)
Marsh marigold (Caltha palustris)
Caltha palustris
Deciduous
Perennials

Marsh marigold, a yellow-flowering plant about 18" high, grows in marshes and the edges of lakes and in moist woodland. Its has scalloped kidney-shaped leaves and a bright yellow flower with prominent stamens full of pollen that attracts many desirable insects.
Wikipedia: "In the UK, Caltha palustris is known by a variety of vernacular names, varying by geographical region. These include in addition to the most common two, marsh marigold and kingcup, also brave bassinets, crazy Beth, horse blob, Molly-blob, May blob, mare blob, boots, water boots, meadow-bright, bullflower, meadow buttercup, water buttercup, soldier's buttons, meadow cowslip, water cowslip, publican's cloak, crowfoot, water dragon, drunkards, water goggles, meadow gowan, water gowan, yellow gowan, goldes, golds, goldings, gools, cow lily, marybuds, and publicans-and-sinners.