I've got something that looks like a pea type plant, growing in the flower bed.

It's been producing yellow, buttercup type petals for around 4 weeks now, but the foliage is what interests me the most. At night, it folds it's leaves closed tight similar to a tropical plants I have, a Guanacaste tree.

It's popped up the past couple of years, and I thought I'd pulled it up last year, but maybe I didn't get the root, or it had only gone to seed.

I don't have a camera at the moment, but I managed to find a picture on another website with someone else trying to ID it, at night, with the leaves closed.

Thanks for any help anyone can provide!

Here is a link that might be useful: