that does look a lot like it but that link said this. (Hydrocotyle sibthorpioides is a small species native to southeastern Asia.) and these things are growing in the very backyard of USA? Sort of unbelievable because it seems as this plant lived at that place seasonally for many years.
You were very close if not exactly right. Here is the name that was listed in my state website. Hydrocotylesibthorpioides Lam.