The Unknown

I started this begonia from a leaf I snitched off the floor when the landscape crew at a local touristy-like place was ripping them up last fall. The flowers were beautiful, mostly double pinks and yellows from what I saw, but not sure what plant this exact leaf came from. (I wasn't bold enough to ask). The plants must have been a good 2 foot tall and quite bushy. The leaf was a little smaller than my hand and a nice, deep green.

The flowers looked like 'Non-Stop', but the leaves don't look the same. Heck, I don't even know if its a tuberous type or not. Ok, so I don't have any experience with begonias!

Any ideas from what the leaves look like?

I'm not even sure of how to get it through the winter. It's looking ridiculously healthy at this point, and I'd like to keep it that way. I didn't even think it would work when I slit the leaf and plopped it on some soil, but I'm happy it did.

Help. Anyone?

*Edit 8/28 : I posted these same pics on the Begonia forum, and they don't think it's a begonia at all! Hmmm...I used fresh potting soil from a new bag, scored the leaf a few times, layed it on top of the soil and covered it with a ziplock. And this is what popped up! Now, I'm kind of weirded out about what it might be.

Someone suggested geranium, but I don't have any of those anymore (and there aren't any for miles around - I live in the boonies), so doubt it was some sort of errant seed. Especially considering it was a brand new bag of potting soil. Well, then...I hope it lives so I can see what kind of gift plant I got! :)

*Edit 9/3 : Someone guessed it might be a Ranunculus - and they might be right, as the leaves look darn close! Now, where would that have come from?! I better be able to keep this thing going until it blooms. It's driving me nuts...