Mayapple

Yes,Podophyllum peltatum.

you will soon have lots of wild lemon fruits, the plants are poisonous and can cause skin irritation so be careful handling them.

Thanks for the help, all. Supposedly the fruit, when quite ripe is edible (in small amounts). Anybody try it?

You may be confusing them c Maypop, or passion fruit.

From the link below...
Comments: Mayapple is a familiar woodland plant with interesting foliage. It develops very quickly during the warmer days of spring. There is no other plant within the state that resembles it; the only other species in this genus occur in Asia. People can eat the ripe berries in limited amounts, even though they may be mildly toxic. The flavor is bland and resembles an overripe melon.

Here is a link that might be useful: Podophyllum peltatum

Interesting...
I always thouht they were completely toxic.