I have Ranunculus " buttered popcorn" isn't for in the pond is more of a bog plant, stands in water from November til this time of year (July) when the back edge of our yard finally dries. Stays green all winter and can be invasive, but is a very pretty plant. LMK if you would like some I have plenty to share.

Fourpaws I think you may be confuing R aqautilis with R lingua grandiflora or R flammula.
R lingua grandiflora is also known as water buttercup, R lingua grandiflora or R flammula are also know, respectively, as greater and lesser spearwort they are marginals/bog plants.
R aquatilis is an aquatic, like water hawthorne or water lilies.