This section is from the book "Commercial Gardening Vol2", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
This is the common British Marsh Marigold or Kingcup, sold for planting by the sides of lakes, streams, etc. It flourishes in rich muddy soil on river banks and streams, and the large bright-yellow Buttercup-like flowers are picked and sold in bunches in spring by costermongers. There are a couple of double-flowered forms.