Can anyone identify this weed? Folks at the garden store couldn't (and
they had a specimen to view)

Anyway, thought I'd take a shot and ask you gardening experts

It looks a lot like a fern: dark green oblong rounded leaves extend
perpendicular from a woody reddish-colored stem. There are little
balls under the leaves along the stem (spores?).

The weed has appeared late in the summer and really seems to like the
cooler wet weather. It's spreading all over the yard.

The question is, what is it and how do I get rid of it? That is, is it
perennial or will it die off over the winter.

tia for any advice
Doug