Looks like the non-native wood poppy, Chelidonium majus (link to Wikipedia entry below). Wish my weeds were as pretty and interesting.

Here is a link that might be useful: Chelidonium

Probably could have identified it just by the description of the sap. No other plants in our area have that. It's a common weed but should be easy to control by pulling. Stylophorum diphyllum would make a good replacement if you like the look of it.

Whew... thanks for the info. Good to know it isn't like the poisonous poke weed I was cultivating so gloriously last year. LOL

I think this is the last one left, so I'll leave it be. From the looks of the seed pods plenty of re-seeding will be going on for future generations.

Yes, I love my beautiful weeds.

How amazing!!! I just read the wikipedia information catspa linked. This is celandine!!!! I've been wondering where I could get celandine plants. I guess I just didn't look in my own back yard.

This is not the native celandine poppy, as indicated earlier. That would be Stylophorum diphyllum.

pashta_2006 - this is Greater Celandine, Chelidonium majus, not to be confused with Celandine Poppy, Stylophorum diphyllum, or lesser Celandine, Ficaria ranunculoides. Which 'Celandine' were you looking for?