My wife and I were given a pot of vines as a gift, and the plant in this picture ended up growing out of the pot. The previous owner has no idea where this plant came from. Over the last month it's grown straight up almost four feet and has single-petaled yellow pentagon-shaped flowers at the top. Pictures below. Can anyone tell us what this is?
I'd agree with Eric - Physalis of some sorth. It looks very very much like what are commonly called "Cape Gooseberries" - although your plant does not have the black ring inside the flower, so it may also be a Tomatillo. Wait until it fruits. Many of the Physalis species bear edible fruits; it will be easier to identify the species by seeing both fruit and flower.
