Looks like Caltha palustris, Marsh Marigold. It likes pond and stream edges. But could be wrong if a plant from the USA!

It was growing at the bottom of a hill near the banks of the East River so you could be right. Thank you.

It looks like lesser celandine to me as there are single flowers from a stalk from the base of the plant. it is a nuisance in many gardens here. it grows from small brown tubers and spreads readily. having said that it is pretty and dies down totally by the end of April.
it does better in slightly damp soil and is a woodlander really.

Marsh marigold has several flowers per stalk.

You answered many of my questions. It is pretty in the woodlands, so I'll just let it stay there. Thanks

I think SBG is right, Ficaria verna not Caltha. I didn't look carefully enough!

I always said she knows her stuff! Ain't it the truth? :)

took a lot of learning though! landgirl and I often get the wild flowers correct and if we aren't sure the other one comes up trumps. :o)

I don't know if they are poisonous but don't go eating them anyway; just in case :o)

I promise I won't eat them; cross my heart, hope to die.

The roots used to be used for treating haemorrhoids - bit of sympathetic magic there, judging by the shape of the little corms... (You probably didn't want to know that, lol)
I have been busy watering a lawn with Weedol this afternoon to kill off a determined invasion of the little dears.

I just read that it's in the buttercup family and is poisonous and invasive. It could be lethal to grazing animals. Better to be left in the woods. This was interesting - thanks everyone.