I love social media for this alone: In my previous post of Native Wood Poppy, I got a heads up that I have an imposture, not the true Stylophorum diphyllum in the garden.
Slightly bummed, but now grateful to know the difference - I have it's Eurasian cousin: Chelidonium majus.
Oh, well. The bees don't seem to mind. I may lift out more of the seedlings I was going to nurture.
I've been told the Native Wood Poppy has larger flowers (this one is about the size of a twoonie).
The dead give-away, are it's seed pods. Stylophorum diphyllum have seed pods that droop and look similar to the flowering buds. Here, the Chelidonium majus have long bean pods that point upwards.
Thanks, Shawn! I appreciate the learning curve!
The good aspect: I can now dead head these seed pods to prevent them from seeding all over!