large leaf, hollow stem

I have another plant brought into our MasterGardener clinic that I would appreciate some help with. The client said it's growing in her woodland yard. The leaf is about 6.5 inches across. The underside is significantly lighter that the top side. The stem is about 1/2 inch in diameter and is hollow. Any ideas? Thanks again for all your help! She brought in 10 samples, and this was the only one that stumped me.

 

Plume poppy.

 

I think you're right about that. Initially I thought it was palmate coltsfoot, but the leaf texture isn't right, and the edges have very pointy serrations. Thank you!

 

That doesn't produce tall leafy stems, and the leaf shape of plume poppy is distinctive.

 

Yes, the leaf is very distinctive, and now that I know what it is, I won't forget it. Thanks again!