In the United States, the marsh marigold (Caltha palustris), appearing in wet places in early spring and often used as a pot herb. It is nearer to a buttercup than to a true cowslip. See Illust. of Marsh marigold.
Cowslip is a character in Watership Down. He is a rabbit and a member of Cowslip Warren. He leads and welcomes Hazel's band of rabbits to Cowslip Warren.